Psittacine Birds

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138
Psittacine birds
Introduction
The order Psittaciformes contains parrots, macaws, cock-
atoos and lories. This order is extremely well reviewed
and illustrated by Rowley (1997) and Collar (1997).
Rowley suggests 6 genera of Cacatuidae (cockatoos) with
21 species, Collar describes 78 genera of Psittacidae (par-
rots, macaws, lories) with 332 species; Sibley & Ahlquist
(1990) suggest 358 species in 80 genera; other authorities
suggest minor variations to these numbers.
Parrots may be defined by their distinctive, well-
developed, hooked rostrum (upper beak) with a promi-
nent cere (the featherless area dorsal to the upper beak);
the rostrum is hinged to the skull by a synovial joint in
large birds (e.g. macaws) and an elastic zone in small
birds (e.g. budgerigars); this feature is unique amongst
birds, and there are some unique muscles associated
with the jaw; the prehensile feet are zygodactyl, hav-
ing digits I and IV directed caudally and digits II and III
cranially; there is a well-developed crop, proventriculus
and gizzard, but there are no caeca; the gall bladder is
usually absent; the preen (uropygial) gland is tufted or
in some genera absent, e.g. Amazona and Pionus; the
furcula (united clavicles) is weak or absent; the syrinx
has three pairs of intrinsic muscles, is tracheal and well
developed, having a syringeal valve at its entrance.
Parrots nest in holes, lay white eggs and have nidi-
colous (stay in the nest for a long time) young, which
are ptilopaedic (covered with down when hatched).
Adult parrots have patches of powder down; these are
areas of down feathers which fragment at their ends
and cover the bird and its plumage with a soft, usually
white, powder (Fig. 7.1). The other more esoteric ana-
tomical characteristics that define the order are covered
more comprehensively by Sibley & Ahlquist (1990),
who also conclude that parrots have no close living
relatives.
Psittaciformes are commonly referred to using the all-
embracing term ‘psittacine birds’ (or psittacids) and are
very popular as either caged pet birds or aviary birds.
Psittacine birds range in size from the hyacinth macaw
(Anodorhynchus hyacinthinus), which measures 100 cm
and weighs 1500 g (although the kakapo (Strigops hab-
roptilis), a flightless parrot, is even heavier at 2060 g),
down to pygmy parrots, e.g. the buff-faced pygmy
parrot (Micropsitta pusio) at slightly less than 10 cm
and weighing 11 g. The numbers within a species vary
Nigel H. Harcourt-Brown 7
from 37 individuals for the Spix’s macaw (Cyanopsitta
spixii), to being very numerous and considered a pest
species, e.g. some cockatoos (Cacatua spp.) in Australia.
The family is mainly vegetarian; some of its members
are specialized feeders, such as the lories and lorikeets
that eat only pollen and nectar.
The attraction of parrots as companion animals is in
their intelligence and potential for taming and training,
their ability to mimic vocally, and their rounded faces
which most people find an attractive feature in any ani-
mal. Not every species of parrot can be kept in captivity,
either because of rarity, or more usually dietary require-
ments, e.g. pygmy parrots (Micropsitta spp.) which eat
mostly lichens and fungus. A few psittaciform families
provide the general public with many of their pet birds.
The following concentrates on species that may usually
be encountered in captivity.
Macaws
Macaws range in size from the hyacinth(ine) macaw
(A. hyacinthinus) at 100 cm to the noble macaw (Ara
nobilis) at 30 cm. They are characterized by large beaks
and long tails. They are South American in origin and eat
nuts, seed, berries and fruit. The immensely strong beaks
of the larger birds, such as the green-winged macaw (Ara
chloroptera), are able easily to break open Brazil nuts.
Macaws are very strong and potentially destructive; they
require large cages or stands, but are best kept in aviaries.
Fig 7.1 Powder down feathers on the flank of a cockatoo.

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CHAPTER 7: PSITTACINE BIRDS
7Parrots
Parrots are short-tailed, large-beaked, stocky birds.
There are several African parrots, the commonest in
captivity being the grey parrot (Psittacus erithacus – and
known commonly as the ‘African grey parrot’). It is the
familiar black-beaked, red-tailed, grey parrot. There is a
subspecies, the Timneh grey parrot (P. e. timneh), which
is smaller and darker, with a horn-coloured beak and
a dark maroon tail. Both come from West and Central
Africa. They live in woodland and eat seeds, nuts and
berries; they are particularly fond of palm oil nuts and
will raid maize crops, causing much damage.
Another commonly encountered family of parrots is
known as Amazons (Amazona spp.). Out of nearly 30
species in the family, three are commonly kept: the blue-
fronted Amazon (A. aestiva), which is mainly green
with a blue and yellow face, a red carpal edge – easily
visible when the bird is perching normally – and a red
wing spectacle on five or more secondary feathers; the
orange-winged Amazon (A. amazonica), which is also
green with blue and yellow feathers around its face but
an orange wing spectacle and no red on its carpal edge;
and finally, the yellow-crowned Amazon (A. ochro-
cephala), which is green with a green face and a yellow
patch somewhere on its head or neck, with a red wing
spectacle and a red carpal edge. These birds come from
Central and South America, where they live in forests
and eat fruit, berries, nuts, blossoms and leaf buds.
There are many smaller parrots that are popular as
aviary subjects. These include Pionus spp. and Brotogeris
spp. from South America, and lovebirds (Agapornis
spp.), Senegal parrots (Poicephalus senegalus), Meyer’s
(brown) parrots (P. meyeri) and brown-headed parrots
(P. cryptoxanthus) from Africa. Lovebirds are very pop-
ular, several species being completely captive bred with
a huge variety of colour mutations.
Cockatoos
Cockatoos (Cacatuidae) are medium- to large-sized
birds, usually white, and nearly all have an erectile crest
that can be raised when alarmed or excited. The popular
pet cockatoos are the sulphur-crested cockatoo (Cacatua
galerita), lesser sulphur-crested cockatoo (C. sulphurea)
and the Moluccan cockatoo (C. moluccensis), which is
a pale pink colour. There are other species of various
colours, including black, white, pink or even nearly red.
Cockatiels (Nymphicus hollandicus) are also cockatoos.
All are very gregarious birds and are Australo-Pacific
in origin.
Cockatoos are very noisy, even by parrot standards!
They eat a varied diet of fruit, berries, nuts, flowers, leaf
buds, roots and also insects and their larvae which they
may dig out of the ground or from trees. Black cocka-
toos are seldom kept as pets in Europe.
Parakeets
Parakeet is a term restricted to small parrots with long
graduated tails. There are many genera and they are
mostly Pacific and Asian in distribution. Australia will
not currently export any birds, but its parakeets have
been popular in captivity for generations, due to their size
and muted voices (compared with other Psittaciformes!);
they are also less destructive in the aviary and are pret-
tily coloured. In Europe most parakeets are cheap to buy.
They are not usually kept as pets, except for the budgeri-
gar (Melopsittacus undulatus). Other Australian species
including grass parakeets (Neophema spp.) and rosellas
(Platycercus spp.) are frequently kept as aviary birds. New
Zealand has provided the aviculturalist with the kaka-
riki (Cyanoramphus novaezelandiae). Asian parakeets
are all very similar and are from the genus Psittacula;
they include the rose-ringed or ring-necked parakeet
(P. krameri), the Alexandrine parakeet (P. eupatria), the
plum-headed parakeet (P. cyanocephala), the blossom-
headed parakeet (P. roseata), etc.
Conures
Conures are South American parakeets, and range from
the small and quiet Pyrrhura spp. to the medium-sized,
noisy and destructive Aratinga spp. Many Aratinga
conures are similar in form and habits to the small
macaws, to which they are closely related.
Lories and lorikeets
Lories tend to be larger (approx. 30 cm, and lorikeets
smaller (approx. 15 cm), but all are from the same fam-
ily: Loriidae. They are typified by their brilliant colours
and Australo-Pacific origin, and they have a modified
brush-tipped tongue which they use to collect and com-
press pollen into a pellet so they can swallow it. Pollen
is their main protein source, but they also eat nectar
when available plus occasional insects and fruit. They
are very popular amongst aviculturalists and their diet-
ary requirements can now easily be met by supplying
proprietary ‘nectar’ mixtures.
Pet parrots
The earliest known captive pet birds were from the par-
rot family. There are records of Alexander the Great
bringing ring-necked parakeets with him from India to
Europe. Budgerigars (Melopsittacus undulatus) were
first seen alive in Europe in 1840, and over the next
40 years many tens of thousands were imported from
Australia. From the naturally found, predominantly
green-coloured, yellow-faced bird a huge variety of
colours has been produced, although a red budgerigar
has yet to be bred! Adult male birds of most colours

HANDBOOK OF AVIAN MEDICINE
140
(but not lutinos, which have yellow feathers and pink
eyes, or albinos, with white feathers and pink eyes) have
a blue cere; adult females have a brown cere.
The best time to obtain a pet budgie is when it first
leaves the nest, at around 6 weeks old. At that time the
bird has feathers edged with black or brown, that give a
barred appearance to the frontal region (forehead) above
the cere (Fig. 7.2). These barred feathers are moulted at
the first partial moult about 2 months later, leaving the
forehead a plain colour. Male ‘barheads’ have a pink-
ish cere with a blue tinge; however, this is not a reliable
guide to gender. Also, females bite far harder than males,
even when still babies in the nest! It is unfortunate that
budgerigar breeders have developed what is known as a
buff plumage for their show birds. The buff feathers are
very large and appear to have deformed barbules as they
do not unite to form a normal contour feather shape.
Buff feathers have a hairy appearance. Breeders’ budger-
igars also tend to live only about 4 years. ‘Mongrel’ pet
budgerigars seem to live far longer, and 8 years is aver-
age, although the author has seen a budgerigar, with a
dated closed- ring, of 21 years.
The cockatiel was named by a bird-fancier,
Mr Jamrach, being an English adaptation of a Dutch/
Portuguese word for little cockatoo (Newton 1896).
By the end of the nineteenth century the cockatiel was
already a popular pet caged bird and has remained
so ever since. The general grey colour, with orange
cheeks and a distinct head crest, is present in males and
females. However, the male has a yellow face and crest
while the female is grey; the male’s orange cheeks are
brighter; the tail and wing feathers are solid grey in the
male, whereas they are mottled grey and white (espe-
cially underneath), in females. Cockatiels of this colora-
tion are termed ‘normals’, but there are many colour
variants – lutino (yellow), white, fallow (with a brown-
ish tint), etc. Immature birds resemble females.
The cockatiel is a peaceful, active, cheerful bird that
mimics well; it deserves its popularity and would be the
author’s first choice for anyone wanting a pet bird. It is
also relatively cheap to purchase, house and keep.
Grey parrots are very popular pets, and are hardy,
medium-sized (450–500 g) birds. The reason for this
parrot’s popularity is its talking and mimicking ability;
erithacus means mimetic. Unlike the popular ‘mynah
birds’ (which are not in fact mynahs but grackles,
Gracula religiosa), these parrots will learn new words
and noises throughout their lives. They are usually
friendly throughout their entire lives but hand-reared
birds do often feather-pluck, especially when sexually
mature. A large cage or small indoor aviary is required
to keep them happy. Like all parrots, when kept on
their own they need to fly around and have a lot of
human contact, but are destructive and should not be
left unattended. They tend not to like water, either as
a bath or when sprayed. However, it is still necessary
to spray them or let them bathe at least weekly to keep
their plumage in good condition. Grey parrots also tend
very quickly to become ‘hooked’ on a seed-only diet.
The Timneh grey parrot is smaller and more subdued
in colour. It is, however, as satisfactory as a pet as its
close relative. Its treatment should be the same.
To some extent the age of many species of parrot can
be deduced from the iris. This structure is important to
the bird as its movement is effected by skeletal muscle
and is therefore under conscious control. The bird can
use the iris to signal to other birds (owners and vets)
by expanding the iris to cause a flash of colour. During
the first year of life of parrots such as greys, Amazons
and macaws the colour of their iris slowly changes.
Newly weaned birds have blue/brown irises, which
change to yellow in greys and large macaws, or orange
in Amazons. (See also Chapter 3, Figs 3.7–3.10.) Some
species of cockatoo have a brown iris if female and a
black iris if male, while in the juvenile it is a neutral
hazel colour. As parrots become sexually mature the iris
brightens, while in later life the iris becomes thinner and
less pigmented, and in old age there are often degenera-
tive eye changes such as cataracts (Clubb & Karpinski
1993). Old age is considered to be 45 to 50 years in
macaws, and 35 years in greys and Amazons. Reports
of a life expectancy of 100 years are rarely true.
The orange-winged Amazon is imported in large
numbers and not usually bred in captivity, unlike the
blue-fronted Amazon; a number of ingenuous owners
have been sold the cheaper orange-winged Amazon as a
more expensive blue-fronted Amazon. Amazon parrots
like fruit and vegetables as well as a seed diet.
Blue-fronted, orange-winged and yellow-fronted
Amazons are all popular as pets, although various other
species are also kept. In the main they are not as talented
Fig 7.2 A young budgerigar. The barred feathers extend to the cere,
which is turning blue showing that the bird is male. The barred feathers
are lost from the forehead at about 12 weeks old; this bird is known
as an opaline and its head will have no barred feathers. Most adult
budgerigars, known as ‘normal’ have bars from the middle of their head.

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CHAPTER 7: PSITTACINE BIRDS
as the grey parrots at talking, but are considerably more
attractive. Amazons (and Pionus spp.) all enjoy being
sprayed and will hang from the bars of their cages and
fan their tails and wings to get as saturated as possible
when being sprayed. They enjoy being outside in the
rain and in the UK acclimatized parrots living in aviaries
can be seen bathing happily in sleet or even snow! They
much prefer to be sprayed in the morning, and seem
unhappy about going to roost wet. Amazons are much
less likely than greys to feather-pluck as they get older,
but often change temperament in the breeding sea-
son and single pet birds can become quite dangerous,
attacking and biting humans that they think are rivals.
This behaviour is not apparent outside the breeding
season. Also in Amazons, behaviour initiated in stress-
ful situations is manifested by apparent irritation to the
skin and feathers.
Amongst the macaws, it is only the larger birds that
are popular as pets, because of their size and colour;
they are very striking. The green-winged macaw is very
gentle and pleasant and probably makes the best pet; the
blue and yellow (gold) macaw is also popular. The scar-
let macaw looks very attractive and is a reasonable pet
bird when young, but it becomes very spiteful and even
aggressive when adult, especially when sexually active.
All the macaws have loud voices and will use them, espe-
cially at first light. The macaws may have their wings
clipped to prevent them flying, but they still need a very
large cage or indoor aviary to exercise in. A large free-
standing cage can be made quite economically by cutting
5 cm security mesh into panels and wiring them together.
These birds tolerate being sprayed and some even like it.
They can all mimic and talk to a reasonable degree.
Cockatoos are kept by some people, but they are
the most prone to psychological disturbances and can
become very unhappy on their own, even when atten-
tion is lavished on them by their owners. They are very
noisy, more so even than the macaws. They can become
very depressing pets and are the most likely parrot to
self-mutilate, drawing blood when they chew through
their skin into muscle. I have yet to see a pet Moluccan
cockatoo that does not have some chewed feathers.
Owing to the noise and psychotic behaviour, cockatoos
frequently get passed on through a serious of owners,
thus exacerbating their behavioural problems.
Housing
Most psittacine birds are better kept as individual pairs
in aviaries made of stout wire mesh. There should be a
space between pairs of parrots, or they will attack the
toes of neighbouring birds and amputate them. A con-
venient method of aviary construction is to suspend the
cage above the ground. The cage should be a reasona-
ble size for the species being housed, and should allow
the birds room to fly. Birds are happier being able to get
higher than their keeper and so a minimum height for the
roof should be two metres, even if the cage is only one
metre high and wide, which is suitable for lories, small
parrots, conures, etc. Suspended aviaries minimize con-
tact with old food, faeces, etc., and make cleaning very
easy. Ideally the suspended aviaries should be enclosed in
a large netted area to prevent escape if a bird gets out of
the cage whilst being caught or fed, and also to minimize
contact with wild birds and their diseases or parasites.
Aviaries should be made from wire ranging from a
19-gauge 2.5  0.5 cm mesh for small birds, to 16-
gauge 5 cm mesh for macaws, etc. The wire should be
galvanized. In some parts of the world (not the UK),
this galvanization process seems to cause zinc toxicity
to the birds when they are first housed, and it is recom-
mended that new mesh is washed in dilute acid first.
Environmental enrichment
Corvidae (crows) and Psittaciformes (parrots) have,
relatively, the largest avian cerebral hemispheres;
Galliformes (fowl-like birds) and Columbiformes (doves
and pigeons) the smallest. Psittacine birds (and crows)
appear to be very ‘intelligent’. However, the interac-
tion between the ability to learn and the various related
behavioural reflexes makes this statement contentious.
Mentally normal parrots prefer to be kept with others of
the same species and they must also have the facility to
perform functions other than sitting, eating and sleeping.
Cages must be large enough for flight, birds should have
different-sized perches of varying materials and there
must be a suitable environment for foraging, playing and
other social interactions. Perches made of smooth hard-
wood will cause pressure problems on the plantar aspect
of the birds’ feet, similar to bumblefoot in birds of prey.
To avoid this, perches of different shapes and diameters
(preferably branches covered with bark) are very useful.
The birds will chew and destroy these branches and they
must be replaced regularly. The author has tried many
different woods in his aviaries (sycamore, elm, ash, haw-
thorn, elderberry, pine, pine treated by tannalization,
etc.), and has yet to find any wood that is toxic to the
parrots. However, it would be prudent not to use woods
known to be poisonous to mammals such as rhododen-
dron or yew. Loops of hessian rope suspended from the
roof of the cage also make good perches, as there is some
‘give’ as the bird lands. The same may be accomplished
by anchoring one end of a branch with a hinge or hook
and eye and suspending the other end from a piece of
wire; again this allows the perch to move more naturally.
Nutrition
Although parrots eat a wide range of foodstuffs they
are primarily vegetarian. Birds that live in tropical or
subtropical forests and woodland eat a wide range of

HANDBOOK OF AVIAN MEDICINE
142
Vertebtae
Clavicle
Coracoid
Scapula
Humerus
Radius
Ulna
Ribs
Synsacrum
Grit
Patella
Osteodystrophic femur
Fibula
Tibiotarsus
Pubis
Pygostyle
Trachea
Rostrum
Clavicular air sac
Carina (Keel)
Artery
Heart
Osteodystrophic ribs
Parabronchi
Caudal limit of lung
Liver
Proventriculus
Intestine
Gizzard
Kidney
Tail feathers
Fig 7.3A Ventrodorsal view of an adult grey parrot.

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flowers, fruits and seeds; those living in drier conditions
eat mainly seeds, especially xerophilic (adapted to dry
conditions) birds such as cockatiels and budgerigars.
There are some specialized feeders: lories and lorikeets
(Loriidae) which eat pollen and nectar and have a spe-
cialized tongue with a border of brush-like projections
to aid them; pygmy parrots (Micropsitta spp.) eat lichen
and fungi as a staple part of their diet. Many parrots
have been found with insects in their crops when exam-
ined by zoologists (Forshaw & Cooper 1973), and in a
number of species insects and grubs form a significant
part of their diet.
All animals require carbohydrate, protein and fat in
their diet. Psittaciformes are no different and thought
must be given to the food content of each part of the
diet that is fed to a captive bird as well as its palatability.
Fig 7.3B Lateral view of an adult grey parrot.
Gonad
Notarium
Parabronchi/Lung
Scapula
Humerus
Aorta
Pulmonary artery
Trachea
Crop
Clavicle
Coracoid
Syrinx
Sternum
Heart
Ribs
Proventriculus
Liver
Spleen
Tibiotarsus
Gizzard
Femur
Pubis
Intestines
Cloaca
Pygostyle
Tail feathers
Head of femur
Kidney
Sandbag
Synsacrum

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144
Parrots require diets that contain about 20% protein,
and vegetarian diets must be carefully balanced to avoid
major deficiencies of important foodstuffs. Finally, and
most importantly, parrots must NOT be allowed to feed
selectively, or a well-balanced diet becomes a deficient
diet. Dietary deficiency in captive birds plays a huge part
in determining the bird’s general life-long health.
Seeds
It must be borne in mind that many pet shops sell all-
seed diets as ‘parrot-food’, ‘parrot-mix’ or ‘cockatiel-
food’, and give this to owners asking for suitable food
for their pets. Loose seed sold like this does not have
a ‘best before’ date and could be several years old
even before it arrives at the shop. Seeds such as sun-
flower, peanuts and pine nuts are low in calcium, vita-
mins A and D and protein; they are also very high in
oil. Cereals and smaller seeds, such as millet, are similar
but have less oil and more starch; they are similarly defi-
cient. Seeds are variably deficient in iodine. In a survey
of budgerigars (Blackmore 1963), 85% had dysplasia of
the thyroid gland; this will still be the situation for budg-
erigars that are fed on loose seed from the pet shop.
When given the opportunity, many pet parrots (espe-
cially the greys) become habituated to eating only seed,
especially sunflower seed, and appear to refuse to eat any-
thing else; long term, this is a life-threatening situation.
Fruit and vegetables
Fruit and vegetables are useful in the diet but are often
low in protein, calcium and vitamin D. They are high in
fibre, contain vitamins A and C, and are low calorie com-
pared with seeds. It is preferable to use non-sludging fruit
and vegetables such as apples and carrots. Food pots must
be kept clean, as a build-up of vegetable debris encour-
ages the growth of Aspergillus spp. and various poten-
tially pathogenic bacteria. This is especially common in
warm, damp climates.
Pulses
The seeds of leguminous food plants are known as pulses.
Peas, beans and maize (sweetcorn) are all very useful
foods, as they contain good levels of protein (20–30%).
However, be aware that they contain around 60% car-
bohydrate and are also low in calcium. Soya bean protein
contains the most similar range of amino acids to those in
animal protein. Soaking pulses and allowing them to ger-
minate increases their digestibility, decreases the toxin con-
tent of some beans, and improves their taste. They should
be prepared by soaking for 24 hours. Too warm a temper-
ature allows fermentation; too cool prevents germination.
The pulses should then be washed thoroughly in clean
running water, which removes any noxious metabolic
products and also any potentially fermentative bacteria.
After initial soaking the pulses may be kept moist and cool
in the fridge for several days, but they must be washed
daily and before use. In warm climates it may be better to
boil the pulses just prior to feeding rather than soak them;
boiling reduces the risk of fermentation.
Minerals
Most seed-eating small parrots appreciate grit to
aid their grinding gizzard, but there is discussion
as to whether or not it is essential in larger species.
Mineralized grit and oyster shell grit are used. Oyster
shell grit does not last as long in the gizzard but is a
good source of calcium. Care must be used not to over-
use mineral grit, to avoid the risk of impaction, a quar-
ter to half a teaspoonful once a week with the food is
usually sufficient. Grit sold for pigeons is satisfactory
for most medium and large parrots. Mineral blocks
containing calcium or iodine are produced for small pet
birds and can be useful, as is cuttlefish; again the bird
has to eat this solid material and not all birds will.
Vitamin supplements
All parrots require a vitamin and mineral supplement
with their food unless they are fed on an appropriate
all-in-one commercial ration. There are a large number
of supplements on the market. Water-soluble products
seem not to contain the range of compounds found in
powders. Mixing powder with seed works reasonably
well but it is better to take the fruit and vegetable por-
tion of the diet, chop it up and mix it with the seed.
This gives a wet mixture, which is a very satisfactory
vehicle in which to mix the powder. A specific avian
vitamin and mineral supplement should be used, as this
will contain a better balance of vitamins and minerals.
BEWARE: many owners will feed a vitamin and min-
eral supplement in too small a quantity, and often infre-
quently; occasionally owners will feed several different
brands at once plus cod-liver oil and therefore give a
completely unbalanced amount of vitamin D. In either
case there can be disastrous consequences.
Commercial diets
All-in-one diets have become widely available and are
theoretically a good idea. There is no doubt that an
appropriate all-in-one pelleted diet is far better than a
badly balanced diet; it also overcomes the problem of
selective feeding. However, self-selection from a wide
range of foodstuffs can be a good way of feeding a bird
but small quantities of each food item and a sensible
dietary balance must be struck if selective feeding and
nutritional deficiency are to be avoided. Constraining
the individual bird to eat one dietary mix long term is

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certainly boring for the bird and also may produce nutri-
tional problems over the years. This is especially possible
as so many parrot species have different and inadequately
researched nutritional requirements. Very few, if any,
diets have been fed unchanged to significant numbers of
individual birds for even a decade. Manufacturers have
relied on the fact that breeding birds show dietary defi-
ciency much more quickly than pet, caged birds. As gen-
eral advice to pet bird owners an all-in-one diet should
take the place of a seed mix and a proportion of various
types of fruit and vegetables should be included.
Pet grey parrots and cockatiels are the most frequently
malnourished birds. Both of these will do well on pelleted
diets, but there can be major problems changing many of
these birds onto their new regimen. Amazons, pionus,
macaws and cockatoos have a much greater liking for
fruit and vegetables and appear less likely to become mal-
nourished. However, selective feeding will cause problems
even in these birds. Cage-confined Amazons and budgeri-
gars particularly will over-eat and become obese.
Protocol for dietary change
Under veterinary or informed supervision the bird and
its droppings should be observed for a few days to assess
what is normal. The owner should be encouraged to
regard parrot seed as sweets, cookies and crisps: treats
that may be used as reward and positive reinforcement,
but not a sensible staple diet. The bird should be weighed
daily for a few days before the dietary change starts.
Once the new diet has been selected, this alone
should be placed in the cage in the morning and the
food intake monitored. If no food is eaten during the
day, some of the previous (well-loved) diet in a small
quantity may be mixed in for 15 minutes in the evening.
Grey parrots can get enough calories for 24 hours from
about a tablespoonful of sunflower seed, so if too much
seed is provided they need not eat until the following
night. Each morning give the new diet and provide less
seed in the evening.
Alternatively the new diet can be mixed with the old
diet and the ratio of the mixture altered over a period
of time until the bird is provided with and eating 100%
of the new diet and none of the old.
Throughout this time, the bird’s weight should
be monitored, daily if possible, and the droppings
observed. A lack of faeces indicates that there is no food
being eaten. Owners will always worry that their bird is
likely to die of starvation; this is unlikely with the larger
parrots but is a possibility with cockatiels, lovebirds
and budgerigars. The author had one Amazon who did
not eat for 8 days but whose weight dropped from (a
too fat) 550 g to only (a still fat) 500 g over this period;
on day 9 she ate the new diet well and continued to do
so thereafter. However, this is not an ideal method of
changing the diet and has potential dangers.
As the new diet is eaten, enzyme systems in the gut
and liver will change to accommodate the new food
intake. The faeces will also change and on a fruit and
vegetable diet the faeces will enlarge and lighten in col-
our, there will also be more fluid voided. Overweight
birds with fatty livers will adjust more slowly, and must
be regarded as high-risk patients. In these cases fasting
is a danger, and it is useful to feed these birds and birds
with other subclinical illnesses with a hand-rearing for-
mula twice daily using a crop tube. This provides the
birds with a well-balanced diet and prevents ‘starva-
tion’ whilst the birds acclimatize to their new diet. This
is the preferred method for ‘converting’ the parrot that
has refused to change its diet at home: invariably by the
fifth day of crop-tube feeding the parrot starts to eat the
all-in one diet. It requires the bird to be an inpatient.
Table 7.1 indicates average weights for various spe-
cies. It can be seen from this table that although it is
easy to produce a guide for an average weight it must
not be relied upon as a weight for the individual. The
weights in the table have mostly been taken from birds
in the author’s clinic that were anaesthetized after hav-
ing endoscopic gender determination; they were not
fat and were starved. In some cases there were too few
birds to give an average weight. The weights for wild
birds have been taken from Dunning (1993).
Breeding and determination of gender:
‘sexing’
All parrots form a strong sexual bond. They mature
sexually between 1 and 5 years of age depending on the
species; smaller birds such as budgerigars are able to
breed at 1 year old. A few parrot species are obviously
sexually dimorphic, notably eclectus parrots where
the males are predominantly green and females are
red and purple. In others the differences require closer
observation:
l many of the small lorikeets (Charmosyna) or
cockatiels have obvious colour differences in
their adult plumage although it is difficult to
differentiate them when they are immature as they
all tend to have the female coloration
l many species of white cockatoos, when adult, have
a brown iris if female and a black one if male
l most adult male budgerigars have a blue cere and
females a brown one (Figs 7.2 and 7.20B).
On casual inspection the majority of remaining
Psittaciformes are sexually monomorphic; however,
there are still subtle differences that may be seen by the
experienced observer – for example:
l grey parrots are blacker if male and grey if female
l orange-winged male Amazons have very much
broader heads than females

HANDBOOK OF AVIAN MEDICINE
146
l most male pionus parrots have a larger eye than
the females.
Individual variation makes these slight differences
difficult to see in every individual and for many avicul-
turalists the birds’ gender must be determined by endo-
scopic examination of the gonad or genetically from
DNA. Parrots, like most birds, can see ultraviolet light.
Reflection of light in the ultraviolet wavelength shows
that some birds have sexual dichromatism based on
colours that we cannot appreciate.
Nesting
Parrots nest in holes. A few species use nesting mater-
ial; some lovebirds (Agapornis spp.) line the nest cavity
with bark or twigs that they carry to the nest held under
their feathers, but most chew up the wood inside the
nest chamber to make a bed for the eggs. One species,
the Quaker or monk parakeet (Myiopsitta monachus),
makes a large communal nest of twigs. Parrots lay
white eggs, usually on alternate days. Incubation com-
mences immediately and this causes the young birds in
the same nest to be different ages. Some of the smaller
parrots lay six eggs, thus allowing 11 days between the
first and last youngsters; there is therefore a dramatic
difference in size between the nestlings, but this seldom
seems to cause a problem. Large parrots lay only two or
three eggs. Baby parrots are nidicolous (helpless when
first hatched and remain in the nest) and ptilopaedic
(covered in down when hatched). The parents regurgi-
tate food directly into the mouths of their chicks. There
is no evidence of the production of crop milk as found
in pigeons (Columbiformes) but, when looking at the
difference in growth rates between hand-reared and
parent-reared parrots over the first few weeks of life,
it is evident that there must be some factor that makes
parent-reared babies grow so much more quickly and
also gives them a greater level of immunity than hand-
fed chicks.
Hand rearing
Many breeders take over the role of parent birds. Eggs
may be removed for incubation as soon as they are laid,
but the hatching rate increases if the parent incubates
them for the first third of the incubation period. Correct
incubation temperature, regular weight loss and turn-
ing are the important factors for successful incubation.
Eggs that are incubated at too high a temperature will
produce deformed chicks, while too much humidity
will prevent hatching or cause oedematous chicks that
do not survive. Too low a temperature or too dry an
atmosphere will kill the chicks. Regular rotation of the
eggs on their long axis (turning) is essential: eight times
daily seems ideal. Failure to turn the eggs results in the
Table 7.1 Weight chart
Species Average weight Range of
weights in grams
(number of birds)
Blue and gold macaw 950–1175 (5)
Green-winged
macaw
1200 1060–1365 (10)
Scarlet macaw 750–1000 (6)
Grey parrot 500 395–585 (26)
Timneh grey parrot 325
Senegal parrot 120 92–160 (14)
Blue-fronted Amazon 350
Orange-winged
Amazon
400
Yellow-crowned
Amazon
500–550 (6)
Maximilian’s pionus 230 200–242 (20)
White-capped pionus 187 166–210 (14)
Bronze-winged
pionus
210 194–228 (9)
Blue-headed pionus 230 206–270 (11)
Lesser sulphur-
crested cockatoo
450
Greater sulphur-
crested cockatoo
800
Moluccan cockatoo 850
Cockatiel 90–110
Budgerigar (wild
birds)
30
Budgerigar (pet birds) 30–85
Peach-faced lovebird
(wild birds)
46–63 (29)
Masked lovebird (wild
birds)
m – 49 (8)
f – 56 (9)
Maroon-bellied
conure
75–80 (7)
White-eared conure 50–55 (5)
Blue-throated conure 90–100 (30)
Painted conure 55–65 (10)
Ring-necked parakeet 120–135 (20)

147
CHAPTER 7: PSITTACINE BIRDS
embryo sticking to the shell membrane, hence causing
difficulty in hatching. Artificial incubation has been
fully discussed by Low (undated).
Hand rearing has been made much easier by the for-
mulation of specific hand-rearing diets by some pet food
manufacturers. All the well-known reputable brands seem
to be satisfactory. Owner-made rearing diets may be very
good, but there is the risk that they may be improperly
balanced and have poor vitamin and mineral content:
they are best viewed with suspicion. There are no excuses
for the production of malformed parrots due to inad-
equate nutrition, but this is unfortunately still very com-
mon. In one study 36 ‘normal’ hand-reared grey parrots
from a variety of sources were examined radiographically;
it was found that 44% of these birds had been affected
by juvenile osteodystrophy as evidenced by deformed
bones (Harcourt-Brown 2003). Baby birds are fed from
a specially shaped spoon or via a syringe or a crop tube;
each of these methods requires patience, dedication and
an immense amount of time. Hand rearing should not be
taken on lightly.
Birds that are being hand reared are usually more
active than birds reared by their parents. Growing
bones are not strong enough for the bird to be able to
run around. Breeders often encourage the baby par-
rots to follow the feeding spoon quite actively or firmly
restrain active baby birds whilst syringe feeding. Both
these actions risk causing bony deformity.
Imprinting occurs in parrots as in all birds. Parrots
that are hand reared without contact with their own
species as siblings and parents become misimprinted.
Misimprinting produces very appealing baby birds
desired by the pet trade but may cause immeasurable
difficulties over subsequent years. Weaning by the new
pet owner, as encouraged by many pet shops, is to the
benefit of the pet shop and not the bird. Hand-reared
birds will often take twice as long to wean as parent-
reared birds.
Clinical examination of the lll parrot
Detailed examination of the bird is covered in Chapter
3 and under each disease section. However, examina-
tion of the cage and cage floor is almost as important
as examining the bird. Owners should be asked, if pos-
sible, to bring the bird in its cage, and the cage should
not have been cleaned out for at least 24 hours. The
cage size (which gives an idea of how much activity the
bird gets), and the types of perches and their suitability
should be noted; toys are a good guide to ‘owner type’;
and food remains will prove or disprove the veracity of
the owner’s assurance that the bird gets a good mixed
diet. Finally, the droppings and regurgitated food on the
floor of the cage tell a story to the clinician.
Post-mortem examination of psittacine birds has been
covered comprehensively by Dorrestein & deWit (2005).
Droppings
Droppings consist of three portions:
1. Water and water-soluble products of excretion –
these are initially excreted from the kidneys and
refluxed into the terminal bowel, where complete
or partial reabsorption takes place. The water
content of the droppings can vary considerably in
illness and health.
2. Urate – a white, pasty, colloidal solution from
the kidneys. Uric acid is not water-soluble and
is secreted by the renal tubule and not filtered
through the glomerulus. The colour of the urate
portion can vary for a number of reasons.
3. Faeces – black, brown or green in colour, usually
having a solid worm-like appearance.
It is useful to become familiar with the normal drop-
pings of the various genera, as droppings vary due to
species as well as diet (Fig. 7.4). Budgerigars and cock-
atiels produce small, dry, comma-shaped droppings;
macaws produce large moist droppings; lorikeets pro-
duce mostly liquid. Faecal consistency reflects the diet:
fruit and vegetable diets give large wet droppings; seed
diets give small dry droppings.
Abnormalities of droppings
1. Watery droppings. Normal birds pass watery
droppings if they are on a diet with lots of soft
fruit or nectar, or if they are scared and pass their
droppings before the water has been removed. Ill
birds with polydipsia or polyuria – e.g. renal or
hepatic disease, diabetes or hyperadrenocorticism –
pass very watery droppings. Neurogenic
Fig 7.4 Normal faeces from a grey parrot that has been fed exclusively
on pelleted food. There is a well-formed faecal mass (due to the high
fibre content of the diet) covered in white urates with very little residual
urine.

HANDBOOK OF AVIAN MEDICINE
148
polydipsia or behavioural causes of polydipsia
are rare. The watery portion should be tested
with a (mammalian) dipstick test, the specific
gravity should be measured, and it should
also be examined microscopically. If the urine
contains particles or is flocculent, it should be
centrifuged before testing. Normal specific
gravity is 1.005–1.020; pH is 6.5–8.0; and
protein should be present as a trace in the urine
but is present in larger amounts in the urates.
Glucose is normally absent; blood, haemoglobin
or myoglobin will cause a similar reaction on a
dipstick and should be absent. The major bile
pigment is biliverdin, which is much greener than
(yellow) bilirubin.
2. Discoloured urates – usually green or yellow.
Urates can be stained by faecal bile in normal
birds, and this occurs especially in watery
droppings. Discoloured urates can be caused by
obstructive hepatitis of bacterial, chlamydial (Fig.
7.5) or viral origin; in these cases very green urates
are due to biliverdin. Prehepatic overload from
haemorrhage or bruising after surgery, trauma or
large volume injections will cause the urates to be
discoloured bronze, light green or yellow (Fig. 7.6).
3. Diarrhoea. This is a mixture of faeces, water and
urates, and can be caused by worry, bacterial
infections, papillomavirus or intestinal parasites.
Diarrhoea on its own is rare in comparison with
the condition in dogs and cats, and a diagnosis of
diarrhoea must be differentiated from the polyuric
bird and also the laying/incubating female. Birds
laying or about to lay eggs store their droppings
for longer than normal, and void a bulky,
abnormal looking mass soon after leaving the nest
site. This change starts a few days before laying
the first egg.
4. Presence of blood. Blood may be mixed with faeces,
and therefore from the bowel, or it may be in the
urinary portion; it is usually difficult to tell. When
seen, lead poisoning, an intestinal obstruction,
e.g. intussusception, or possibly viral, bacterial
or parasitic infestations should be suspected.
‘Amazon haemorrhage syndrome’ is often caused
by lead poisoning. Blood that is not mixed with
the droppings, but appears as drops or spots in or
on the droppings, is usually cloacal in origin, and
can be caused by an infected granuloma, urolith(s),
viral papillomata, a prolapsed oviduct or large
bowel and, very rarely, tumours.
5. Presence of whole seed. If seed is seen, mixed
and coated with the faeces, the commonest
cause is proventricular dilatation syndrome in
parrots, macaws and cockatoos; however, it can
also be caused by megabacteriosis (especially
in budgerigars), trichomoniasis, or other bowel
irritants. If the seed is separate from the faeces it
may be regurgitated.
6. Lack of faeces but presence of urates. This
indicates starvation or an obstruction within the
alimentary tract.
7. Coloured faeces or urates. Pigmented foods,
such as beetroot, or medications – even topical
medication – can change the colour of the faeces
and/or urates (Fig. 7.7).
It is important to look at the faeces microscopically:
smeared, fixed and stained for bacteria, yeasts and
Fig 7.5 The faeces are reduced and wet, the urates contain some
biliverdin and are therefore light green in colour. This parrot was very
unwell; it had a reduced appetite and was polydipsic. The faeces were
lighter in colour, there was copious urine and the urates were bright
green, typical of a bird with severe obstructive jaundice. A lateral
radiograph showed enlargement of the liver and spleen. A PCR test for
Chlamydophila was positive.
Fig 7.6 Although this is typical of birds with a mild hepatitis, this
cockatoo had a severe haemorrhage in one lung and the green urates
were caused by blood breakdown products causing a pre-hepatic
‘jaundice’.
parasites; as a wet preparation in warm (37°C) saline
for protozoa; and as a flotation preparation using a sat-
urated solution of salt (NaCl), sucrose or zinc sulphate
for parasite eggs and cysts.
Regurgitation
As with vomiting in dogs and cats, regurgitation by
birds can frequently be a cause for presentation at the
surgery. It may be due to:
l fear
l travel sickness
l sexual or courtship behaviour – feeding a mate or
young, mirror images (male budgerigars), owners
l drug induced – handling and injections, or oral
administration of various drugs
l proventricular dilatation syndrome
l poisoning or consumption of a gut irritant
l obstruction – goitre in budgerigars,
intussusception, tumours (e.g. papillomatosis) or
foreign bodies
l inflammation of the crop/proventriculus/gizzard –
trichomoniasis, candidiasis, megabacteriosis,
fermented or hot food in hand-fed young birds.
Sampling
A clinical examination will usually require augmenting
with various samples taken for further examination (see
also Chapter 3).
Blood
Blood samples may be obtained from the following
sites:
1. The jugular vein – the right jugular vein is
usually the larger, and lies beneath a featherless

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CHAPTER 7: PSITTACINE BIRDS
area of skin on the neck of the bird close to the
oesophagus and trachea (see Fig. 3.41).
2. The brachial vein caudoventral to the humerus,
or the ulnar vein on the caudomedial aspect of
the wing distal to the elbow. Both these sites
usually require plucking of overlying feathers for
adequate visualization of the vein (see Fig. 3.40).
3. Claws – small amounts of blood can be obtained
by clipping a claw; a few drops are sufficient
for a blood smear or DNA profile for sex
determination. If this sample is to be used for
biochemistry, make sure that there are no urates
on the claw prior to collection.
Blood collected via a 25-gauge needle seems no more
likely to be haemolysed than that obtained via a 23-
gauge needle. Because of high venous pressure and a
poorly developed dermis, haematomata are frequently
formed at under-wing sites. These may be limited by col-
lecting blood under general anaesthesia; by manual pres-
sure on the vein distal to the venepuncture hole using
dry cotton wool; or by using the jugular vein. If the bird
is conscious and struggling violently, the bleeding will
continue while the bird is restrained; replace the bird in
its cage or box and the bleeding usually stops in a few
minutes. Birds can safely have 1% of their body weight
removed in the form of a blood sample. Using the jug-
ular vein, budgerigars (Melopsittacus undulatus) can
have up to 0.5 mL of blood collected; larger birds such
as blue-fronted Amazons (Amazona aestiva), can have
1–2 mL collected from the ulnar or jugular veins. Very
small birds can have a cleaned toenail clipped and blood
can be collected, as it drips, into a heparinized capillary
tube; one (unheparinized) drop may be used to make an
air-dried smear. It should be assumed that the volume of
subcutaneous bleeding will equal the amount removed
for the sample; it rarely does. Vitamin K-deficient
birds and those with lymphoma or severe liver disease
can bleed to death after venepuncture.
Most commercial laboratories will perform haema-
tology and biochemistry on a heparinized sample. Some
authorities prefer it for biochemistry, providing the sam-
ple is centrifuged immediately and the plasma removed.
A heparinized sample yields more plasma than a clotted
sample yields serum; if only a small sample of blood can
be taken then place it in heparin. If a heparinized sam-
ple only is collected then several air-dried smears should
be made of whole blood, from the syringe, immediately
after collection. However, whole heparinized blood
is required by the laboratory to enable a cell count.
Unfortunately whole blood degrades in the post: cellu-
lar components fragment and release enzymes and elec-
trolytes into the serum. Therefore it is more satisfactory
to obtain blood for haematology in EDTA and a gel
heparin tube for the biochemistry. Gel tubes, which are
centrifuged to separate the blood cells from plasma by
Fig 7.7 Dietary pigment in urates, caused by ingestion of beetroot.
parasites; as a wet preparation in warm (37°C) saline
for protozoa; and as a flotation preparation using a sat-
urated solution of salt (NaCl), sucrose or zinc sulphate
for parasite eggs and cysts.
Regurgitation
As with vomiting in dogs and cats, regurgitation by
birds can frequently be a cause for presentation at the
surgery. It may be due to:
l fear
l travel sickness
l sexual or courtship behaviour – feeding a mate or
young, mirror images (male budgerigars), owners
l drug induced – handling and injections, or oral
administration of various drugs
l proventricular dilatation syndrome
l poisoning or consumption of a gut irritant
l obstruction – goitre in budgerigars,
intussusception, tumours (e.g. papillomatosis) or
foreign bodies
l inflammation of the crop/proventriculus/gizzard –
trichomoniasis, candidiasis, megabacteriosis,
fermented or hot food in hand-fed young birds.
Sampling
A clinical examination will usually require augmenting
with various samples taken for further examination (see
also Chapter 3).
Blood
Blood samples may be obtained from the following
sites:
1. The jugular vein – the right jugular vein is
usually the larger, and lies beneath a featherless

HANDBOOK OF AVIAN MEDICINE
150
a barrier of gel, are vital if the blood is to be posted to
the laboratory as they prevent haemolysis and therefore
distortion of the results.
Bacteriological samples
Faecal samples may be obtained from the floor of the
cage, and defecation on new paper is the most satisfac-
tory method of collection. A cloacal swab is too hit-or-
miss; the swab may be collected from any of the three
cloacal chambers, and as it is usually faeces that are
required it is more satisfactory to obtain them after def-
ecation. Because of rapid excretion of many drugs via
the kidney and/or liver, faeces should be collected prior
to any medication.
Samples for PCR tests in the live bird
Cotton buds or swabs on plastic are preferred to those
on wood. For Chlamydophila, it is best to obtain three
samples by swabbing the choana and the conjunctival
sac and take a faecal sample. No transport medium is
needed for these tests. If cost is an issue, swab the cho-
ana in upper respiratory tract cases, the conjunctiva
in cases of conjunctivitis, and faeces collected from ill
birds with urates discoloured green with biliverdin, or
use the same swab and go from conjunctiva, to choana
to cloaca – three for the price of one!
Psittacine beak and feather disease requires live feather
pulp, from an erupting feather quill, to be milked out of
the shaft into a container of transport medium. Whole
blood can also be used: place a few drops into transport
medium.
Polyomavirus tests are most reliable using a cloacal
swab.
Diseases
Diseases of psittacine birds have been studied for many
years, and there are comprehensive accounts of the dis-
eases of parrots in early texts such as those of Zürn
(1882) and Russ (1890). Many diseases were very accu-
rately described, even though the causes and cures for
many of them were obviously elusive and not under-
stood by these early authors.
The dyspnoeic bird: diseases of the
respiratory system
Parrots are frequently presented with a combination
of respiratory signs: sneezing, nasal and/or ocular dis-
charges, noisy breathing, changes in voice and dysp-
noea. Some birds will learn to mimic human coughs and
these birds do not have respiratory disease. Also, clini-
cally normal pionus parrots will hyperventilate when
they are upset or worried.
Examination (see also Chapter 3)
Observe the bird in its cage from some distance away,
give the bird time to relax, and then note its degree of
respiratory embarrassment. Birds with difficulty breath-
ing ‘bob’ their tails up and down with each breath.
Occasionally it is possible to see that the bird has a dis-
tended abdomen. Look for discharges from eyes and
nose, and look at the droppings. Ask the owner about
the duration and severity of any signs; the diet (with
special reference to vitamin A sources); and any previ-
ous treatments and their outcome.
Before catching a bird in severe respiratory distress
warn the owner that this may be a risky procedure but
explain that the bird will never get better if left in the
cage. Catch the bird as gently as possible and keep it
upright; this avoids any fluid in the air sacs swamping
the lungs and drowning the bird. Birds dislike mouth-
breathing, and will attempt to breath through their nos-
trils even when these are obstructed. This means that
it may be difficult to differentiate between upper and
lower respiratory disease when the bird is in its cage.
To examine the upper respiratory tract, catch the
bird, wrap it in a towel and look at its face. The nostrils
should be cleared of discharge and checked for rhinolith
masses. The nostril normally has a small piece of tissue
protruding into its centre – the rostral concha. Observe
the bird’s face from dorsal and cranial aspects for sub-
cutaneous masses or swellings in the infraorbital sinus.
Press gently into the sinus and around the eye to see if
exudates can be forced out of the nostril or lachrymal
duct. Tempt the bird with your finger to make it open
its mouth and examine around the tongue and also look
at the choana; if necessary use a suitable gag. If the nos-
trils are not obstructed and there is no discharge, hold
the beak shut and occlude first one nostril and then the
other: listen for bubbling sounds, stertorous noises or
lack of passage of air. All these indicate problems that
need further investigation.
Some wheezing sounds can be from the larynx if this
is involved in the pathological process. The entrance to
the larynx can be seen with the bird’s mouth held open
by a gag.
Open-mouthed, apparently obstructed breathing and
a change or loss of voice point to a syringeal or possibly
a tracheal problem. Small birds can have their trachea
transilluminated to examine for foreign bodies; part
the feathers along a feather tract and damp them down
prior to this examination. Larger birds can have their
trachea and syrinx examined endoscopically, but this
requires a general anaesthetic. In birds with tracheal
obstruction a general anaesthetic can only be adminis-
tered safely via an air sac tube (see Chapter 6).
Auscultation should always be attempted, even
when the bird is making a lot of (vocal) noise; use-
ful information can still be obtained that can confirm
lower respiratory tract problems. Listen to the ventral,

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CHAPTER 7: PSITTACINE BIRDS
lateral and dorsal aspects of the body on both sides of
the bird. Birds with lower respiratory infection often
have ‘crunchy’ heart sounds, as if the beating heart is
wrapped in crumpled cellophane. The air sacs should
be auscultated ventrally and laterally. The lungs are best
heard on the dorsal aspect of the bird, over the ribs.
Palpate the abdomen for abdominal distension with
fluid or organ/tumour enlargements. This can cause dys-
pnoea by preventing the air sacs from circulating the air.
Many respiratory conditions require an anaesthetic
for examination, diagnosis and treatment. Birds with
apparently only upper respiratory disease frequently
have a concomitant pneumonia which may not immedi-
ately be obvious. It is prudent to treat these birds for a
few days with a broad-spectrum antibiotic, prior to an
anaesthetic.
All birds with respiratory disease should be suspected
of being vitamin A deficient, and their treatment should
include vitamin supplementation. An oral multivitamin
and mineral supplement specifically made for birds is
preferred but changes will take up to a year to occur
fully. Injections of multivitamins may have a short-term
effect, but are occasionally fatal.
Specific problems
Rhinoliths
Rhinoliths are hard crusty lumps blocking the nostril
and causing breathing difficulties. They are very com-
mon in African parrots (Fig. 7.8A) such as the grey
and the red-fronted (Jardine’s) parrot (Poicephalus
gulielmi). Hook the rhinolith out of the nostril using
a small dental osteotome, shaped like a tiny teaspoon
about 1.5 to 2 mm in diameter. This instrument can
be introduced behind the mass and used to lever it out
(Fig. 7.8B). There is frequently mucopurulent discharge
behind the rhinolith in the nasal cavity and occasionally
the sinuses. Clean the discharge out and instil neomy-
cin or gentamicin eye drops twice daily into the nostril,
and re-examine after a week of treatment to clean out
again. If the discharge does not respond to antibiotics,
culture for Aspergillus spp. Medium to large rhino-
liths will deform the bony structure of the nostril (Fig.
7.8C) and will often recur, requiring regular (about 3-
monthly) removal. Vitamin A deficiency will play a sig-
nificant part in this condition. Evening primrose oil will
help prevent hard nasal secretions building up in the
deformed nostril: instil one drop once or twice a week
into the affected nostril(s).
Chlamydiosis
A watery conjunctivitis, which may give rise to a wet
nasal discharge and occasional sneezing, is typical of
Chlamydophila infection. This manifestation of chlamy-
diosis is most common in cockatiels and Australian par-
akeets including budgerigars. The birds are not usually
Fig 7.8A An 8-year-old pet Senegal parrot that lived on a diet mainly
composed of seeds was presented for examination because it was
sneezing and had a slight nasal discharge from its right nostril . A large
rhinolith could be seen blocking its left nostril.
Fig 7.8B The rhinolith was easily removed from the conscious bird
using a small dental probe.
Fig 7.8C Rhinoliths slowly expand, causing a permanent deformity of
the nasal passage. Although the entrance to the nostril will contract to
half the size seen here, the bird will require treatment and permanent
supervision. Treatment can be antibiotic drops (gentamicin eye drops) to
remove infection, a drop of evening primrose oil once or twice weekly to
prevent the nasal secretions from becoming too hard, and regular re-
examination to remove secreted material before it blocks the nostril.

HANDBOOK OF AVIAN MEDICINE
152
unwell, but they can infect other birds, which will die
of the hepatic form of chlamydiosis and are potentially
zoonotic. Confirmation with a PCR test on a con-
junctival or choanal swab is required. Treatment with
chlortetracycline eye ointment and oral or parenteral
doxycycline is usually curative within a month.
Sinusitis
Sinusitis is typified by swellings of the infraorbital area.
Nasal and ocular discharges are also possible signs.
Culture of mucopurulent material obtained by aspi-
ration of the sinus is vital for treatment. Many cases
are colonized by Gram-negative organisms such as
Pseudomonas. Mycoplasma spp. could be involved
in moist sinusitis; enrofloxacin or tylosin will kill this
bacterium. Daily flushing by injecting into the sinus or
flushing through the nostril (Fig. 7.9) is the best treat-
ment for moist sinusitis. Some sinus deposits are inspis-
sated, palpable and too hard to flush out and must be
surgically removed.
Occasionally parrots (especially Amazons) are pre-
sented with sinusitis and/or sneezing. A caseous mass can
be found in the nasal passages, usually by endoscopic
examination through the choana. Culture often confirms
the presence of aspergillosis. This must be treated by
removal of all the pus and regular instillation of an anti-
fungal drug for some weeks.
Choanal abscesses
Choanal abscesses will cause nasal discharge and dif-
ficulty breathing through the nostrils. They are best
seen in an anaesthetized bird. It is usually wise to give
a course of enrofloxacin for 4 or 5 days before anaes-
thesia and surgical removal of the abscess. The abscess
is sometimes seated on the dorsal aspect of the choana
and the edge of the structure must be rolled back to
reveal the abscess. A 21-gauge hypodermic needle is use-
ful as a stylet to open the epithelium, and a small blunt
probe, such as an arthroscopy hook, is needed to push
the inspissated pus out. Again attention to diet and the
addition of vitamin A are paramount.
Foreign bodies
Tracheal foreign bodies will cause severe dyspnoea. A
millet seed is a common foreign body in a cockatiel that
is having difficulty breathing, and transillumination will
show its presence. An air sac tube and general anaes-
thesia give a chance of removal. Stop the seed slipping
down the trachea with a 25-gauge needle through the
trachea distal to the seed, then partially open the tra-
chea with a cut between the rings and remove the seed.
Repair the trachea with fine suture material.
Aspergillosis
Laryngeal aspergillosis has, in the author’s experience,
been a cause of dyspnoea in imported Pionus spp.
Removal of the purulent material from the rima glot-
tidis and treatment with itraconazole or topical clot-
rimazole can be successful, but this condition carries a
surprisingly poor prognosis.
Aspergillus spp. infection of the distal trachea, syrinx
or primary bronchus is a common cause of dyspnoea; it
will also affect lungs and air sacs. This condition should
be suspected in a dyspnoeic bird that is wheezing and
has a change of voice. Diagnosis requires an anaes-
thetic and endoscopy. A 2.7 mm 0° endoscope should be
used to examine this area in Amazons, cockatoos, large
macaws and large grey parrots. A parrot’s trachea tapers
distally, and smaller birds prove impossible to examine
without a smaller endoscope. A general anaesthetic using
an air sac tube will allow suction through a catheter
placed down the trachea and into the syrinx. This tech-
nique can suck out most of the lesion. Treatment with
enilconazole topically and itraconazole orally can be
effective. Clotrimazole by nebulization may be used as
well. The bird should be re-examined a few days later
as the fungus and caseation can regrow. This condition
is common in grey parrots and carries a poor prognosis;
these birds should be referred to an avian veterinarian.
Birds with generalized aspergillosis can be either
acutely affected, in which case they are presented either
dead or with sudden onset of severe dyspnoea; or they
can be chronically affected, in which case they will
Fig 7.9 A lateral view of the skull of a blue and gold macaw (Ara
ararauna) showing the approximate extent of the infraorbital sinus
(broken line), the site of insertion of a hypodermic needle for sampling or
flushing the sinus (arrow), and the position of the pterygoid muscle. The
pterygoid muscle has an overlying artery and vein (and nerve) which
are easily punctured if the needle is inserted too deep. This will cause a
profuse haemorrhage.
For injection, the nostril and eye should be noted and midway between
them it is possible to palpate a bone-free depression, bordered ventrally
by the jugal arch. This space is increased by opening the bird’s mouth. A
needle is inserted here (arrow) directed slightly caudoventrally to enter the
infraorbital sinus. Using a syringe it is possible to aspirate the contents of
the sinus, which should normally be air. In this macaw the needle should
be inserted no more than 5 mm as the sinus is subcutaneous at this point.
Orbit
Craniofacial
hinge
Nostril
Pterygoid
muscle
Palatine
bone Ju
g
al arch
Quadrate
bone
Approximate
extent of the
sinus in relation
to the orbit of a
psittacine
species

153
CHAPTER 7: PSITTACINE BIRDS
present as being unwell (to greater or lesser extent),
underweight (in spite of eating reasonably well) and
dyspnoeic; again the degree varies and is usually wors-
ened by stress and exercise. There is little change in
voice, but examination with a stethoscope reveals an
increase in audible respiratory sounds. Diagnosis is by
clinical examination, and a blood sample will reveal a
very elevated heterophil count (15 000–40 000 cells/dL)
and radiography will typically show a locular pattern
in the lung and/or air sac region. Treatment using itra-
conazole orally and clotrimazole by nebulization can be
successful in producing a cure.
Syringitis
Syringitis can be seen in some birds that have a voice
change and/or an ‘asthma’ attack. Endoscopy will reveal
an irritated syrinx with moist swollen edges to the
syringeal valve and no sign of aspergillosis. This condi-
tion can be brought on by bacterial infection or some
irritant trigger such as cooking fumes. A spasm of the
syrinx can be induced during anaesthesia in some birds
causing fatal asphyxia which may not be noticed in time
to place an air sac tube.
PTFE poisoning
Polytetrafluoroethane (PTFE) poisoning from over-heated
non-stick Teflon®-coated cooking utensils is a common
cause of severe, rapid, terminal pneumonia. Over-heat-
ing is not difficult if the pan is empty, and it causes the
coating to depolymerize to form a lethal vapour; birds
in the same air-space will drop off their perches, dead,
within half an hour of inhaling the vapour. Some self-
cleaning ovens and some spotlight bulbs are also coated
with Teflon®. Examination of the lungs at post-mortem
shows oedematous bloody tissue throughout both lungs.
Over-heated, smoking cooking oil can have a similar
effect, as will bonfire or barbecue smoke.
Air sac worms
Air sac worms can be seen in recently imported birds
as an incidental finding at post-mortem examination or
during endoscopic gender determination. These worms
do not seem to cause disease and can usually be safely
ignored. Treatment with ivermectin should be success-
ful, but could cause problems by producing dead worms
in the air sacs.
Abdominal distension
Abdominal distension produced by tumours, hepatic
or proventricular enlargement, ascites or egg-produc-
tion will prevent the air sacs functioning and cause
dyspnoea: all should be differentiated on radiography,
with the use of contrast and other techniques if required
(see Chapter 5). Serositis will also cause the abdominal
and hepatic peritoneal cavities to fill with fluid and will
cause dyspnoea. This condition appears to be a sequel
to a viral infection.
Diseases of the digestive system
Probably the most common presenting sign for any cli-
nician is the bird that is eating less food than usual and
has loose droppings. It may have lost weight and may
also be regurgitating. Some birds may die suddenly;
other birds may be more chronically affected.
Examination
The owner should be encouraged to bring the bird in
its uncleaned cage: half the clinical signs are found on
the cage floor. Examine the bird from a distance look-
ing for signs of illness, dyspnoea, general condition,
soiled feathers around the vent, etc. Then examine the
droppings on the cage floor. It is uncommon for birds to
have diarrhoea and common for them to be polydipsic.
Normal faecal shape varies between species (see earlier).
The presence of soft, swollen, undigested hulled seeds
with no mixing of faeces is a sign of regurgitation.
The dropping (faecal/urinary mass) may be well
formed if the bird is eating, but will be small, dark
green and watery with white urates if the bird is not.
It may be poorly formed in birds with diarrhoea, but
also in scared birds or birds with cloacal papillomato-
sis/granulation, or cloacoliths. It may be blood-stained,
or coated or mixed with blood. Sometimes droppings
contain whole undigested seeds; this is abnormal. Take
a faecal portion for microscopy and possibly microbio-
logical culture. Check for parasites, bacteria or yeasts.
Next, assess the urinary portion. In birds on a dry
diet such as seed, the urates should be formed and white
with little water. If there is a lot of water in the diet
(fruit, vegetables, pulses, nectar) or if the bird is poly-
dipsic, then there will be a quantity of water passed with
the urates. Metabolites may be visible in the urates: light
green to dark green urates indicate a hepatitis; green
to bronze urates can occur after trauma and bruising
and can also be caused by hepatitis (Figs 7.5 and 7.6);
some topical medications and food colourings will be
excreted in the urine (e.g. topical proflavine can give
yellow urates or beetroot can give purple colouring –
neither affect the bird) (Fig. 7.7). If the faeces contain a
lot of water use a dipstick test to check for glucose, blood
and protein content. It is usually possible to avoid faecal
contamination.
Next, examine the bird: catch it, look in its mouth
and at the tongue; palpate the crop, thoracic inlet, and
abdomen; examine the cloaca. If the crop is distended,
then pass a crop tube and obtain a sample of crop con-
tents. Smear this on a slide and stain it; look for bacteria,
yeasts and protozoa; also look at a wet preparation.
Carry out a microscopical faeces examination – wet and
fixed stained preparations as well as a worm egg count.

HANDBOOK OF AVIAN MEDICINE
154
In the author’s opinion, the commonest cause of an
illness of sudden onset in a single bird with watery drop-
pings is a bacterial hepatitis or enteritis. Heart blood
taken at post-mortem examination within 20 minutes of
death has invariably produced a pure growth of a coli-
form, usually Escherichia coli (but also Klebsiella spp.
or Pseudomonas spp., etc.).
Clinical signs are an ill bird with watery droppings
containing some or no faeces and, often, light green
urates. Some birds will regurgitate food, especially after
travelling or following intramuscular injection. The bird
should be assessed for hydration (crinkly skin around
the eyes or a skin pinch that remains tented); weight
loss, assessed on pectoral mass and weighing; crop pal-
pation and abdominal palpation should be unremark-
able. The vent should be clean.
Faecal examination tests for birds with watery drop-
pings (in order of preference) include:
l faecal flotation for parasites
l microscopy for protozoa: dilute faeces with warm
isotonic saline and watch for jerky swimming
movements of single cell parasites – but note that
particles smaller than a single cell can exhibit
Brownian motion and may be mistaken for
parasites
l Gram’s stain, which may reveal lots of Gram-
negative coliforms rather than Gram-positive
cocci, indicating abnormal gut bacteria
l bacteriology: this may be useful, but hopefully
results will arrive after the bird has recovered.
Check for Salmonella spp.; Salmonella enterica
serovar Typhimurium is common, especially in
imported grey parrots, but can be seen in any birds.
If a diagnosis of bacterial hepatitis seems likely, then
inject with a broad-spectrum antibiotic, use a crop
tube to give the bird some fluids and place the bird in a
warm, darkened cage. If the bird starts to improve, then
it must be fed four times a day with some easily digesti-
ble food by crop tube and injected twice daily with anti-
biotic. If the bird worsens, then a change of antibiotic is
indicated; adequate fluid must also be given.
Further investigation is required in birds that are not
responding to treatment. It can be useful to combine the
following procedures and possibly carry them out under
anaesthetic, as it is less stressful to the bird. Take a
blood sample for haematology and biochemistry: with a
bacterial hepatitis there will be an elevated white blood
cell count with increased heterophils and a left shift;
elevated gamma glutamyl transferase and bile acids but
normal uric acid, urea and glucose. A low albumin level
is useful as a guide to chronic ill health, and a high PCV
and high urea are indicators of dehydration.
After taking the blood sample, slowly inject an intra-
venous bolus of N/5 glucose saline, 5 mL to an Amazon
or grey parrot and up to 10 mL to a large macaw.
Indwelling intravenous or intraosseous catheters giv-
ing continuous fluids are useful but more complicated
(see Chapter 6). Intravenous catheters can be placed in
the basilic vein on the ventral aspect of the wing, by the
humerus. The bird must be restrained from pulling out
an indwelling catheter, so a collar and/or wing strap-
ping is usually necessary. If i.v. fluids are to be used, be
very careful to avoid over-perfusion; use a burette or a
slow injection system. Do not attach a 500 mL bag of
fluid, as it is only too easy to administer the whole bag,
with fatal results.
Radiography should also be carried out at this time,
and in cases of bacterial hepatitis there will be a normal
or enlarged liver and kidneys (septicaemia/bacteraemia)
or a normal liver and large spleen (enteritis). Note that
green urates and a large spleen along with an enlarged
liver usually indicate chlamydiosis, therefore perform a
PCR test.
The gizzard often contains grit, but check for lead,
glass or metallic foreign bodies, all of which can con-
tribute to conditions resulting in hepatitis/enteritis.
Specific problems
Proventricular dilatation disease
Larger parrots, such as grey parrots, macaws and cock-
atoos, may be presented with signs of weight loss and
regurgitation or weight loss and the passage of whole
seeds; they may also exhibit neurological signs such as
trembling and incoordination; many birds will appear
to be hungry and make pathetic begging-for-food
noises. Most of these cases have proventricular dilata-
tion disease (PDD). This is an infectious disease, almost
certainly of viral origin. PDD may be seen in birds of
any age. Diagnosis in the live bird is aided by radiog-
raphy. Lateral and ventrodorsal views often show a
dilated proventriculus and gizzard. A barium meal may
be needed to demonstrate this or to show a slowed pas-
sage of ingesta. Fluoroscopy will reveal that the normal
movement of the gut has been compromised and instead
of peristalsis the wall of the proventriculus and gizzard
‘flutters’ (Storm & Greenwood 1993).
Confirmation of the diagnosis in a live bird may
be obtained in many cases from histopathology on a
biopsy of the crop; this is relatively easy to perform.
Under general anaesthesia (intubation of the trachea is
vital), removal of a portion of full-thickness crop wall
to include at least one large blood vessel will allow his-
tological examination of the autonomic nerves and asso-
ciated ganglia as they are found adjacent to the arterial
supply to the gastrointestinal tract. Approximately 75%
of cases can be confirmed with this test (Gregory et al
1996). A full-thickness proventricular biopsy is prob-
ably better but much more invasive, and carries a grave
risk of peritonitis.

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CHAPTER 7: PSITTACINE BIRDS
Post-mortem examination can be used to confirm the
diagnosis in most outbreaks of this disease, as there is a
high mortality rate. The crop, proventriculus and gizzard
can be variously thin-walled, dilated and impacted with
seed (Fig. 7.10); surrounding tissues often exhibit peri-
tonitis. The duodenum can also be dilated in some birds,
especially cockatoos. Occasionally there is ulceration at
the proventricular/ventricular junction; this ulcer can
perforate with fatal results. The lungs often show acute
aspiration bronchitis and pneumonia. Histopathology is
required to confirm the suspicion of this disease by the
presence of lymphocytic, plasmacytic ganglioneuritis
involving the autonomic ganglia at various levels in the
gut wall. The brain shows similar changes.
Treatment of this disease is possible, and some indi-
viduals recover. Treatment is empirical: a high fibre,
moist diet, with little seed; broad-spectrum antibiotics
to prevent peritonitis and pneumonia (trimethoprim/
sulphonamide is the author’s first choice); and a proki-
netic, cisapride (Prepulsid, Janssen), can be very helpful.
Celecoxib (Celebrex, Pfizer) and meloxicam (Metacam,
Boehringer Ingelheim), both NSAIDs, are also said to
be very useful. The recovered bird could be a carrier.
However, as apparently normal birds can also appear
to be carriers, and as there is no reliable test developed
that can detect the carrier state, treatment seems a
reasonable option.
Papillomatosis
Weight loss, regurgitation and a soiled vent may be
caused by papillomatosis. This disease usually affects
the upper alimentary tract and cloaca of birds that have
been imported from Central America. Hawk-headed
parrots, macaws and some Amazons are those most
commonly affected, and affected birds appear to have
diarrhoea and their vents are soiled with faeces sticking
to the feathers in lumps. (NB: Budgerigars that exhibit
these signs are usually too fat to clean their vents; they
do not have papillomatosis.) On cleaning the vent,
a protruding mass of tissue may be seen (Fig. 7.11).
Check the oral cavity – papillomata are frequently
found around the choana and the rima glottidis, and
these growths can extend through the alimentary tract.
Removal of the papillomata that are causing problems is
helpful. Histopathology will confirm the typical appear-
ance of the lesions. Mild cautery of the lesions around
the vent will often be sufficient. The disease will make
the birds unwell, but this condition alternates with
periods of good health in a cyclical manner; the period-
icity in one closely observed case was around 4 months.
Therefore, any and all treatments seem to work well for
a time. Autogenous vaccines do not cure the disease. A
papillomavirus has never been isolated from these cases,
but a link has been made with a herpesvirus as a cause
of this condition (Phalen et al 1998). In the long term,
many of these birds become affected with malignant
tumours of the pancreas or gall bladder and related
structures (Graham 1991).
Salmonellosis
Salmonella spp. can affect parrots, especially newly
imported birds. The usual isolate is Salmonella
Typhimurium. Affected birds may die suddenly, but
many cases are ill for a period with signs of general sep-
ticaemia: profuse watery diarrhoea; polydipsia/polyuria;
dyspnoea/pneumonia; depression; inappetence and occa-
sionally, neurological signs. Confirmation is on bacteri-
ology. Treatment with a broad-spectrum antibiotic, with
supportive nursing and feeding, will often allow the bird
to recover, but a number of cases remain carriers and
Fig 7.10 A lateral view of a female grey parrot that died because of
proventricular dilatation syndrome. The lateral body wall has been
removed exposing the massively enlarged proventriculus distended by
whole seeds. The seed can be seen filling the proventriculus and gizzard
as well as filling the oesophagus and crop.
Fig 7.11 This Amazon parrot had a dirty vent and was unwell. General
anaesthesia allowed the mass of feathers and soiled feathers to be
removed revealing a protruding mass that is typical of ‘papillomatosis’.
Biopsies were taken and the masses were trimmed back to the fibrous
layer of lamina propria; this layer must not be penetrated.

HANDBOOK OF AVIAN MEDICINE
156
these individuals may or may not be chronically unwell.
Three samples of faeces must be found to be clear of
Salmonella spp. to rule out the carrier state; one sample
is not sufficient. Carriers may be cleared by the use of
an autogenous, inactivated vaccine. Two doses of vac-
cine, 2 weeks apart, have been found to clear carriers;
each dose should be given orally (1 mL) and as a sub-
cutaneous injection (0.5 mL). This regimen gives a sig-
nificant rise in antibody titre (Harcourt-Brown 1986).
Salmonellosis is a zoonosis, and appropriate measures
must be taken. Other coliforms will produce similar, but
usually less dramatic, signs of illness.
Pseudotuberculosis
Yersinia pseudotuberculosis is a common cause of out-
breaks of acute illness and mortality, usually in aviary
parakeets. It is transmitted via faeces from infected
rodents and wild birds. The majority of affected birds
die within a few days, having shown signs of pneumo-
nia, enteritis with wet diarrhoeic droppings, and general
ill health. At post-mortem examination the most acute
cases have an enlarged, patchily discoloured liver, and
more chronic cases have miliary white spots throughout
the liver. Similar changes are found in the kidneys and
spleen. Confirmation by bacteriology is needed (culture
requirements are specialized so warn the laboratory that
this pathogen is suspected), and antibiotic treatment is
required. The drinking water must be kept uncontami-
nated and the flock will recover more quickly if the
water contains either the appropriate antibiotic or a dis-
infectant such as 5–6 mg/L of free iodine or chlorhexi-
dine. Prompt treatment will limit but not completely
prevent deaths in the affected birds; the organ damage
in some individuals will cause their death even in the
absence of the organism.
Digestive problems in budgerigars
Budgerigars are often presented because they are regur-
gitating their seed or a white pasty substance. In many
cases the birds are well and the regurgitation is onto
their mirror or other reflective surface, or onto their
owner. These birds are in breeding condition, and it
is a normal part of their behaviour to try to feed their
‘mate’. Budgerigars that are on an unsupplemented,
shop-bought, loose-seed diet will usually be iodine
deficient (Blackmore 1963), and the goitres that form
can block the thoracic inlet sufficiently to cause regur-
gitation. Goitres may also affect the action of the syr-
inx and cause a wheezing respiration and an altered
(or lost) voice. The enlarged thyroid may occasion-
ally be palpable at the thoracic inlet. Supplementation
with iodine will quickly alleviate the problem: a stock
solution of 2 mL of strong Lugol’s iodine solution is
added to 30 mL of water, and 1 drop of this is added to
250 mL of drinking water, daily for treatment and 2–3
times weekly for prevention. Most proprietary multivit-
amin and mineral powders contain sufficient iodine.
In other cases birds are unwell, losing weight, and
regurgitating sporadically. An ill budgerigar will have
yellowish staining on the feathers around the beak;
is thin; its crop often feels thickened and may be dis-
tended with fluid; the vent is frequently soiled; and the
bird’s droppings are enlarged and wetter than normal.
After some time with these signs many budgerigars
will die. Crop contents should be examined. It is pos-
sible to obtain crop fluid in some birds by milking the
crop contents up the oesophagus, and the birds will
spit out some of the viscous fluid. If this is not possi-
ble, passing a crop tube and introducing about 1 mL of
isotonic saline and then aspirating will give a sufficient
sample for examination. Warmed wet preparations will
reveal Trichomonas parasites. The other cause of these
signs, megabacteria (Macrorhabdus), will show on a
dried and stained smear. Some birds have both prob-
lems. Occasionally yeasts (Candida spp.) are seen in the
smears as well. Treatment with a mixture of amphoter-
icin B (which will kill both yeasts and megabacteria)
and metronidazole (which kills trichomonads) given via
a crop tube or by mouth as a drop, twice daily for a
week, will resolve the signs. These conditions are very
common in budgerigar breeders’ aviaries and in these
cases treatment of the entire flock is needed. Faecal
examination may reveal megabacteria, but only very
fresh faeces will contain recognizable trichomonads. In
all cases negative results do not rule out these diseases.
Megabacteria are in greatest numbers in the proventric-
ulus; trichomonads perish and disintegrate very rapidly.
Post-mortem examination of a recently dead bird will
allow samples to be taken from the oesophagus, gizzard
and crop and examined by the hanging drop technique
and as smears stained with Gram’s method or Diff
Quik. This will give a reliable diagnosis. The diseases
caused by megabacteria, Trichomonas and Candida can
be seen in other psittacine birds.
Parasitism
Examination of faeces from psittacine birds will, on
occasions, reveal various intestinal parasites. However,
some species of birds are more susceptible than others.
Giardia spp. are an infrequent cause of diarrhoea (also
causing feather-plucking in cockatiels) and may be dif-
ficult to demonstrate in the live bird as they are found
in the upper small intestine; organisms should be looked
for at post-mortem examination of a fresh carcass, using
the hanging-drop technique. Australian parakeets are
frequently affected by roundworms; the birds look ill
and this disease will cause sufficient weight loss for the
birds to die. The worms may not be laying eggs, so a
negative faecal examination should not be trusted. It is
vital that every ill Australian parakeet is wormed with a

157
CHAPTER 7: PSITTACINE BIRDS
dose of fenbendazole (Panacur 2.5% Hoechst, at a single
dose of 50 mg/kg) give by crop tube. If possible the bird
should be kept separately so that the droppings may be
examined over the next 2 days for dead worms. A small
parakeet may contain up to 50 large worms (Fig. 7.12).
Roundworms, in this author’s experience, are the com-
monest cause of death in this group of parakeets.
Macaws (Ara spp.) with low-grade ill health may be
seen passing large wet droppings. Examination of the
faeces by flotation in saturated salt solution will reveal
the typical eggs (small with bipolar plugs) of Capillaria
spp. In-contact birds may also be infested, and fae-
cal samples should be checked. Affected birds must be
dosed regularly with fenbendazole and great attention
must be paid to hygiene or re-infestation will result.
Outdoor cages, suspended in a sunny position, with fre-
quent showering/hosing of the birds and cage, and with
2-weekly dosing with fenbendazole on an individual
basis is required to remove this problem.
Chlamydiosis
The disease caused by the organism Chlamydophila psit-
taci may be known variously by the names chlamydophi-
losis or chlamydiosis, ornithosis, or – most commonly –
psittacosis, since it is always linked with parrots. It was
first reported in humans and psittacine birds in 1895
(Morange 1895). However, it has been found in many
species of birds, especially domestic ducks and pigeons.
In parrots it can give rise to several syndromes.
Firstly, there can be symptom-free carriers that can shed
the organism intermittently and may remain carriers for
many years. The carrier state is commonest in Amazon
parrots and in commercially bred cockatiels and budg-
erigars. Secondly, some birds become extremely ill with
a severe hepatitis: they are depressed, lose weight, may
have respiratory signs and have droppings in which
the urate portion is often a vivid green colour due to
biliverdin levels in the blood rising above the renal
threshold (owing to obstructive liver disease) (Fig. 7.5).
These birds have been previously uninfected, and have
then contracted the disease. In the author’s experi-
ence, grey parrots seem to be uncommon as carriers
but very susceptible to the disease, which is frequently
caught from a symptom-free carrier such as a cockatiel.
Thirdly, some birds, especially Australian parakeets,
are presented with a unilateral or sometimes bilateral
conjunctivitis; occasionally these birds are also unwell.
Finally, some birds become chronically ill as a result of
chlamydiosis and may even develop immunocomplex-
linked glomerulonephritis.
Birds with chlamydiosis should be treated (provided
the zoonotic potential is not significant), as many will
make a complete recovery and – with adequate treat-
ment – will not be carriers.
Diagnosis is best attempted using a PCR test to
detect the organism. Blood samples for antibody levels
and ELISA tests are less easily interpreted and less relia-
ble. Ideally, three samples should be taken: a swab from
the conjunctiva, a swab from the choana and a faeces
sample. The test result will take some time, so presump-
tive treatment should be instituted immediately. Two
drugs kill Chlamydophila in vivo: enrofloxacin and
doxycycline. It is now considered that doxycycline is the
more effective drug, and this can be given by injection,
in food or in the drinking water. Doxycycline must be
administered for 45 days to cure the bird in most cir-
cumstances. All birds should be checked after they are
‘better’, and providing that three samples taken at dif-
ferent times give a negative PCR result the bird can be
considered ‘cured’.
Avian tuberculosis
Occasionally, parrots are presented with weight loss
and/or slowly growing lumps. These birds may have
Mycobacterium avium. Smears from strange-looking
masses may frequently reveal acid-fast organisms. Many
of these birds are excreting the bacillus and it is possible
to identify this using a PCR test for M. avium. Although
some cases have been treated there is a zoonotic poten-
tial (for immunosuppressed people only) as well as the
health of other birds to consider. Birds suffering from
avian tuberculosis should be euthanized.
Diseases of the urinary system
The truly polydipsic bird is often presented, although
owners often confuse polyuria with diarrhoea.
Budgerigars, cockatiels and grey parrots seem most
commonly affected, but perhaps because they are the
most frequently kept pets.
Examination should include looking at the bird in the
cage for signs of general illness, dehydration, abdominal
distension, dyspnoea or leg weakness. The droppings
should then be checked for consistency of faecal portion,
Fig 7.12 Roundworms in droppings from a parakeet.

HANDBOOK OF AVIAN MEDICINE
158
quantity of water and colour of the urates. Finally, the
bird should be removed from the cage and examined
in a routine manner. Many of these birds will be on a
deficient diet, so this should be borne in mind.
An important point is that birds are uricotelic. They
produce uric acid in the liver as an end product of pro-
tein catabolism. The uric acid is excreted via the kidney
as a colloidal solution from which all the water can be
reclaimed, either within the renal tubule or by the termi-
nal bowel. Uric acid is excreted by the tubule; urea and
other water-soluble products are filtered via the glomer-
ulus. After excretion via the ureter, the urine is carried
by retroperistalsis from the urodeum into the terminal
intestine, where water is reabsorbed leaving only urates.
By producing uric acid (insoluble) and not urea (water-
soluble) a uricotelic animal can develop in a shelled-egg
without being poisoned by the waste products of protein
catabolism. In embryonic birds the uric acid is deposited
within the fetal membranes, i.e. outside the fetus.
Renal disease can be very difficult to diagnose. Uric
acid levels tend to remain unaltered even when there is
chronic disease because the uric acid is laid down within
the body cavities. Radiography may show enlarged
kidneys; an intravenous pyelogram, using iohexol
(Omnipaque, Nyomed) is useful to enhance their outline
and show the presence of tumours. Endoscopy is useful,
and an approach between the last two ribs allows visu-
alization of the pericardium, the surface of the liver and
the air sacs – all common sites for deposition of uric
acid (visceral gout). (Fig. 7.13). Puncturing the oblique
septum allows the kidneys to be seen and biopsied. All
these tests may be helpful but not necessarily diagnostic
in early cases of renal disease. Later stages of the disease
may show elevation of phosphorus and a change in the
calcium/phosphorus ratio. A blood sample in which the
plasma has been separated from the cellular component
within 30 minutes should be used for this assessment;
delay in separation from blood cells will increase the
phosphorus levels in the plasma.
Hepatitis (see earlier) and diabetes will both cause
polyuria. In cases of diabetes a urine ‘dipstick’ will
show glucose in urine. Normal urine will contain no
glucose. The pancreas of birds contains little insulin
and this hormone appears to have a lesser role in glu-
cose metabolism than in mammals. Injections of mam-
malian insulin have little effect and dietary change is
the most sensible method of control. Cockatiels are very
commonly affected with this condition and they tend to
eat a seed diet that is rich in carbohydrate. Changing to
an all-in-one diet is very useful in these cases and fre-
quently makes the bird much better. Some of these birds
have pituitary tumours and are Cushingoid.
Renal tumours are common and often palpable within
the abdomen. Because the lumbosacral plexus is sand-
wiched between the kidney and the pelvis, renal tumours
often cause paralysis of a leg rather than polydipsia. A
unilateral lameness in a budgerigar should always be
investigated for renal (or gonadal) enlargement.
Visceral and articular gout
These syndromes are commonly seen in parrots. The
birds are often unwell, and pasty white uric acid depos-
its may be visible under the scaly skin of the legs and
feet (Fig. 7.14). The uric acid will also be deposited
around the viscera in the various peritoneal cavities
(hepatic, pericardial, etc.) (Fig. 7.13). Affected birds
seldom recover. Allopurinol has been suggested as a
treatment because it works in humans (a 100 mg tablet
crushed in 10 mL of water; 1 mL of this solution added
to 30 mL of drinking water). However, its efficacy in
birds has been questioned as it has been shown to cause
gout in some birds.
Diseases of the reproductive system
The most frequently presented reproductive problem
is egg binding. Female birds that may or may not have
laid previously are presented as unwell, slightly dysp-
noeic and usually with a palpable abdominal mass. The
bird may also have difficulty standing and appear very
weak. The most frequent cause is a lack of calcium. The
egg-bound bird is usually on a poorly supplemented
diet and may, as is the case with many pet cockatiels, be
laying her 10th or even 20th egg that year. The diagno-
sis should be confirmed radiographically, when an egg
should be visible. The egg has usually started to form a
shell, but this demand on calcium cannot be sustained.
Fig 7.13 Visceral gout with urate deposits thickly coating the heart.

159
CHAPTER 7: PSITTACINE BIRDS
Parrots lay an egg every other day. The egg takes
nearly 48 hours to form and spends 80% of this time in
the shell gland. The shell gland (uterus) is a part of the
distal oviduct, and when it contains a shelled egg this is
often palpable through the abdominal wall. It is useful
to know when the last egg was laid. Oral supplementa-
tion with calcium and a little vitamin D3 may be used;
a bolus of a high-calcium powder (Nutrobal, VetArk
in the UK), containing 200 mg calcium in 1 g of pow-
der, is mixed with a small amount of cereal-based baby
food and given into the crop with a crop tube. A dose
of 100 to 500 mg of calcium (depending on the bird’s
size) is usually sufficient to allow the bird to be able to
stand, and the egg is usually passed. If the egg is not
passed after calcium administration, oxytocin and vari-
ous other treatments have been suggested. Oxytocin has
profound effects on blood pressure in birds and should
be used with caution in small incremental doses. It has
been suggested that dinoprost (Lutalyse, Upjohn) is
a better choice, but neither of these drugs is favoured
by the author. If the egg can be seen radiographically
or palpated, an anaesthetic followed by gentle pressure
on the egg will force it through the vagina and out of
the cloaca. Another method of removing thin-shelled
eggs is to introduce a hypodermic needle through the
abdominal wall into the egg and to aspirate the con-
tents. This allows the shell to collapse, and the egg is
easily expelled. Occasionally eggs are not passed out of
the oviduct and torsion of the oviduct should be sus-
pected; this requires a laparotomy for egg removal. In
cases such as this ecbolics are contraindicated.
Birds that have been egg-bound need to have their
diet and husbandry fully reviewed. Vitamin D3 defi-
ciency is just as important as calcium deficiency.
Diseases of the central nervous system
(CNS): the wobbly and/or convulsing parrot
Parrots are frequently presented unable to stand on
their perches, and the clinician must differentiate those
birds that are very ill from those with CNS problems.
The commonest presenting neurological sign is of a
bird that is exhibiting incoordination, to the point of
falling off its perch and having some degree of unsteady
or jittery movement. Nystagmus is sometimes seen, but
anisocoria is rare. Some birds convulse and some even
spin around and around continually until they die.
Clinical examination is usually unrewarding.
There are many causes of neurological signs, includ-
ing the following:
l Parrots eat or chew any new object; poisoning
is therefore a common cause of neurological
problems. Lead from paint, solder, lead shot, etc.
are all common causes of lead poisoning.
l The next most common neurological problem
is calcium/vitamin D3 deficiency. This is more
frequent in grey parrots. An all-seed diet, no
supplementation, and sunlight that is filtered
through glass (which removes ultraviolet light),
must all be contributory factors.
l Zinc toxicity will give neurological signs, and is
usually seen in aviary birds in aviaries made with
new galvanized mesh, or in caged birds with cheap
galvanized clips and links on toys.
l Paramyxovirus will also cause irreversible
neurological signs, and in the UK is usually
seen in Australian parakeets. These birds will
convulse, but are usually affected by torticollis and
exhibit very abnormal movement which is often
permanent.
l Proventricular dilatation disease will cause
neurological signs (tremors and muscular
weakness), especially in young macaws which are
making ‘baby-bird’ noises and are also off their
food, regurgitating and looking unwell.
l Some birds with advanced renal and/or hepatic
disease can exhibit neurological signs.
l Hypoglycaemia will cause collapse and brief
convulsions before the bird dies.
l Old parrots are increasingly seen by clinicians, and
some of them develop neurological signs. Some of
these birds are suffering from atherosclerosis of
the arteries in the brain; others have non-specific
cellular degeneration; rarely they have brain
tumours.
Fig 7.14 The typical appearance of urate deposits under the skin on the
leg of an Australian parakeet. These parakeets are often affected by ‘gout’.
This bird was euthanized and internal examination found substantial
urate deposits within its pericardium and on its liver.

HANDBOOK OF AVIAN MEDICINE
160
If a bird is presented suffering from seizures or other
neurological problems, the first step (as always) is to get
a good history, with poisoning and dietary deficiency
in mind. If lead poisoning seems to be likely, then radi-
ography will usually reveal very radiodense particles
in the gizzard (Fig. 7.15). These particles are denser
than grit, which may also be seen on the radiograph. A
blood sample must be taken for lead (lithium heparin
blood is used for this estimation) and calcium (heparin
or clotted blood) estimation. It is important to measure
ionized calcium as this gives a true picture of available
calcium. Normal levels in grey parrots are between 0.96
and 1.22 mmol/L; any results below 0.75 mmol/L should
be considered suspicious and the parrot treated.
If lead poisoning is suspected, then treatment should
be undertaken whilst waiting for the result. Sodium
di-calcium edetate may be injected safely as an undi-
luted intramuscular bolus; this seems to work as rap-
idly as a diluted intravenous bolus and is very safe.
Improvement will be seen within 24 hours. The intesti-
nal tract will have been inactive prior to treatment but
quickly recovers, and the lead is often ground down by
the grit in the gizzard over a 2-week period, providing
that the antidote is given every other day. Treatment
should continue for a week after the lead is seen to have
gone on follow-up radiographs.
If the lead is not being removed by normal digestion
it is possible to remove it in parrots by flushing it out
of the gizzard. The bird should be anaesthetized, intu-
bated, and suspended upside down at an angle of about
45°; a wide bore tube (the sheath from a 4 mm endo-
scope is ideal, or a 5 mm wide inflexible tube of some
sort) is then introduced through the mouth and into
the distal proventriculus. A small catheter is threaded
through this tube until it is in the gizzard, and water
from a syringe connected to the catheter is then used
to flush the gizzard clear of grit and lead. Water at less
than body temperature will rapidly cool the bird to a
dangerous level of hypothermia. Peanut butter has been
suggested as a gastrointestinal lubricant, but it is dif-
ficult to see how this works in vegetarian parrots that
easily digest vegetable oils.
Calcium deficiency should also be corrected without
waiting for the laboratory result if this will take some
time. An oral bolus of calcium-rich vitamin and mineral
supplement (Nutrobal, VetArk contains 200 mg of cal-
cium per gram of powder) should be mixed with a small
amount of food such as human baby cereal or parrot
hand-rearing formula. Calcium-rich solutions usually
contain far less calcium than powders, and hypertonic
calcium solutions are unpalatable and will also cause
the bird to regurgitate. An injection of multivitamins is
not necessary and may even be contraindicated: excess
vitamin D can remove calcium from already depleted
bones and, being fat soluble, it will last longer than the
oral calcium. Most hypocalcaemia cases are suffering
from other dietary deficiencies, so twice daily crop tub-
ing with hand-rearing formula and a calcium supple-
ment is usually required for about 7 days for optimum
results. Needless to say, correction of the diet is required
long term.
If paramyxovirus (PMV) is suspected then a sample
of serum should be sent to a laboratory for antibody
levels. Paired samples may be necessary; 1 mL of clot-
ted blood is usually sufficient, but if the birds are small
then advice should be sought as to the most appropriate
serotypes to test as it may not be possible to take 1 mL
of blood safely.
Paralysis
Birds are frequently presented with weakness or even
paralysis of their limb(s). This has usually developed
over days to weeks and is rarely acute. Budgerigars
seem frequently to be affected.
Firstly examine the bird in its cage and ascertain
which leg is involved. Catch the bird and check the limb
for swelling, crepitus or muscle wastage. Examine any
closed ring to make sure that it has not become too tight
and trapped the limb; this will cause gangrene. If the
ring is too tight then it must be cut off. This will fre-
quently require an anaesthetic, especially in larger birds.
If there is crepitus, the leg must be examined radiograph-
ically and any fracture stabilized by internal or external
fixation. If there is muscle wastage, the limb and also the
whole body should be radiographed in two views.
Nerve injuries are quite a common cause of paraly-
sis. In budgerigars the cause is often a tumour of the
gonad or kidney; this may be seen radiographically, and
Fig 7.15 A lateral radiograph of a cockatoo that was regurgitating
and unwell. The bird can be seen to have a dilated proventriculus and
radiodense particles within its gizzard. The bird was treated with sodium
di-calcium edetate by alternate day injections. The bird recovered
within 2 days, treatment was continued for five injections and by day 10,
radiography showed that all the particles of lead were gone from the
gizzard. A lithium heparin whole-blood sample could have been used to
confirm the diagnosis but the owners found the source of lead in their
house: an antique chandelier that the bird had been roosting on!

161
CHAPTER 7: PSITTACINE BIRDS
can often be palpated through the abdominal wall. If
the radiograph shows an amorphous visceral mass the
tumour may be delineated by giving a barium meal,
which will show the displacement of the intestines. Such
tumours are invariably inoperable. Kidney infections
can also cause a unilateral or bilateral paralysis. The
lumbosacral plexus runs between the kidney and the
pelvis and is therefore easily compressed by enlargement
of the kidneys. Infection can spread from the kidney to
the nerves, causing a neuritis and subsequent paresis.
Most of these cases seem to be due to a coliform infec-
tion and respond to broad-spectrum antibiotic therapy.
Deficiency syndromes
Invariably, birds that have signs of a single nutritional
deficiency will have more than one deficiency problem.
Treatment of a single deficiency will allow the other
deficiencies to show at a later date.
Calcium and phosphorus in the diet should be in
1.5–2.0 : 1 ratio. Seed diets have low calcium and may
contain phytates, which further reduce the available
calcium and phosphorus levels. Vitamin D precursors
are present in vegetarian diets but require metabolism
by ultraviolet light to be converted to the usable form:
vitamin D3.
Calcium and vitamin D3 deficiencies will lead to egg-
binding and osteoporosis in breeding birds and osteo-
dystrophy in growing birds. Unobstructed egg-binding
may be relieved by injecting calcium solution or admin-
istering it orally. Oxytocin may or may not be useful in
these cases as the bird is more likely to be calcium defi-
cient than oxytocin deficient. Osteodystrophy may result
in fractures of long bones in adult laying birds as well
as growing babies. Although only one limb may be frac-
tured, the whole bird should be radiographed because
other bones will be affected. Badly affected birds should
be euthanized. Some cases may be repaired surgically.
Fits due to hypocalcaemia most commonly affect
adult pet grey parrots that have had a seed diet and no
access to sunshine except through glass windows (see
earlier).
Vitamin A is essential for growth, optimum vision
and maintaining the integrity of mucous membranes.
Vitamin A deficiency predisposes to upper respira-
tory diseases and alimentary tract diseases by causing
the mucous membrane’s simple epithelium to become
stratified, squamous, keratinized epithelium. The kera-
tin plugs the ducts of the mucus-secreting and salivary
glands, causing pustule formation and even salivary
gland abscesses. In breeding birds there is decreased egg
hatchability and in (poultry) chicks it prevents the kid-
neys from excreting uric acid which remains visible in
the kidney and ureters (this is commonly seen in post-
mortem examination of grey parrots, the species most
frequently seen with hypovitaminosis A).
Vitamin E deficiency should be considered in pet,
caged birds that have muscular weakness, and also in
birds that are failing to come into breeding condition. It
is especially common in cockatiels.
Iodine deficiency causes delayed moulting and
feather disorders, as it is the usual cause of thyroid defi-
ciency. The thyroid will become enlarged and may cause
dyspnoea with ‘squeaking’ breathing and a change in
vocalization.
Lack of sulphur-containing amino acids (commonly
deficient in all seed diets) and polyunsaturated fatty
acids affects the plumage. The feathers appear dry and
brittle. Their feather barbs fail to interlock, and the
feathers look hairy rather than intact. Dirty feathers can
look similar: spray the bird daily with warm water.
Hyperglycaemia and fatty liver occur in a high per-
centage of cockatiels, Amazons, and many grey parrots
on all-seed diets. All-in-one diets are the best way of
overcoming this problem.
Infectious viral diseases
Avian influenza
Influenza viruses come in three groups; B and C affect
humans and rarely birds; influenza type A affects birds
and rarely humans. Avian influenza has affected parrots
causing anything from no illness to sudden death; or
death after depression, diarrhoea and neurological signs.
However this is a virus that is rarely seen in parrots and
most psittacine infections have occurred either in quar-
antine stations where it was caught from other birds
in the quarantine station, or it has been caused experi-
mentally. Avian influenza virus varies considerably in its
pathogenicity, and the serotypes that affect poultry are
not usually a great risk to parrots and vice versa.
Paramyxovirus
Newcastle disease (PMV-1) and several other paramyxo-
virus strains have caused disease in Psittaciformes. The
signs can be peracute death; respiratory disease or gas-
trointestinal disease or a combination of both; chronic
central nervous system disease (sudden onset and incur-
able opisthotonus, torticollis, tremors or paralysis). It is
an uncommon disease in parrots, and is not seen in sin-
gle pet birds. The disease is diagnosed on virus isolation
from the trachea, lung and brain. This range of viruses
will cross the species barrier very readily and is highly
contagious.
Herpesvirus
This is the cause of Pacheco’s parrot disease: a sudden-
onset, usually overwhelming, hepatitis. Many birds
that are ill will die. Some that recover and some that
are subclinically infected will become lifelong symp-
tom-free carriers. In stressed or low-grade unwell birds,

HANDBOOK OF AVIAN MEDICINE
162
e.g. imported birds in quarantine, the morbidity and
mortality are high. In healthy birds that are well fed the
morbidity seems to be much lower, but mortality is the
same. Post-mortem signs include a very enlarged liver
and some enlargement and darkening of spleen and kid-
neys. Histopathology reveals intranuclear inclusion bod-
ies, and it is possible to isolate the virus. Treatment with
aciclovir may work, but it is not known how this affects
the carrier status of recovered birds. Vaccination with
a dead vaccine is available in the USA, but not legally
obtainable in Europe.
The virus is not the same as those affecting owls,
hawks and pigeons, and there is no cross-infection from
these species.
Psittacine beak and feather disease
This common disease is caused by a circovirus that
occurs in wild Australian cockatoos but is known to
be able to infect nearly all species of Psittaciformes.
It has an affinity for growing cells and will therefore
affect growing feathers, causing the feathers to drop out
before maturation. The virus typically causes signs in
younger birds. Contact with the virus during the growth
period is the common method of infection, and feather
dust from affected birds is highly infective; faeces less
so. The bird becomes unwell, and the virus affects rap-
idly growing cells and will cause feather loss by pre-
venting further feather growth in the fledging birds. The
feathers lose their blood supply, pinch off at the base
and fall out of the follicle; the quill will have a small,
sharp, pinched-off appearance at its tip. The quantity of
feather loss varies with the individual (Fig. 7.16). The
virus will affect the rest of the skin and powder down,
giving a dirty plumage and a black shiny beak, which
is particularly evident in cockatoos. It will reduce horn
production in the beak, and can also affect the bone
marrow and cause a rapid and almost complete reduc-
tion in the heterophil count. Birds infected later in
life have less obvious clinical signs, but as the disease
progresses the bird becomes unwell with various sec-
ondary infections exacerbated by the suppression of the
immune system. Growing feathers fall out and fail to
regrow, and feather colouring can be affected: grey par-
rot feathers become pink (Fig. 7.17; see also Fig. 3.36),
vasa parrot feathers become white instead of black (Fig.
7.18), and the beak and claws degenerate as the keratin
is not formed at the base of the claw, allowing infection
to cause a slough. The course of the disease is magni-
fied by its immunosuppressive nature, but even when
treated, affected birds always die, usually of second-
ary infections or organ failure. It is possible for adult
birds to carry the disease, especially cockatoos. Young
birds are most frequently seen infected, especially when
hand reared. The earlier that they are infected, the more
Fig 7.16 This young hand-reared Senegal parrot was brought for
examination because its large wing and tail feathers were falling out. The
breeders had a mixed collection of parrots, including ‘healthy’ cockatoos,
none of which were tested for circovirus. The bird appeared very healthy
but it had no powder down: its beak was clean and shiny and feathers were
not dusty. A blood smear showed very few white blood cells and almost no
heterophils. There were no actively growing feathers so a 23-gauge needle
was used to obtain a small sample of bone marrow and blood using a
proximal tibial approach. This was positive for circovirus using a PCR test.
Fig 7.17 This 2-year-old Timneh grey parrot was unwell. It had been
kept in the presence of pet cockatiels and other parakeets by its owner
since acquiring it at 10 weeks old. The bird was anaesthetized for
radiography. Its newly growing primary and secondary feathers were
deformed and instead of being uniform grey they were pale in some
areas and pink in others. Feather pulp from this bird was positive for
circovirus on a PCR test.
Fig 7.18 Vasa parrot with PBFD, showing white feathers instead of
dark grey.

163
CHAPTER 7: PSITTACINE BIRDS
rapid and dramatic is the disease. Haematology in many
cases, especially from grey parrots, Senegal parrots and
other African parrots, will show severe depression of
the heterophil numbers and, on occasions, anaemia and
a general leucopenia. These birds may not necessarily
show beak deformity or much feather loss. Definitive
diagnosis is by a PCR test using a DNA probe pro-
duced by the University of Georgia, which is available
in Europe and America via commercial veterinary labor-
atories. This test will confirm the presence of the virus
in live feather pulp, which is the best method for clini-
cal cases. Symptom-free carriers should be detected by
a PCR test on a sample of blood (or better still, bone
marrow) as well as feather pulp.
This infection is a common subclinical problem in
many captive budgerigars. It is one of the causes of
‘French moult’ where the budgerigar fails to grow its
major feathers and is doomed to run around the floor of
the cage. Subclinically infected budgerigars in pet shops
shed the virus and this commonly infects baby parrots
that are being sold from the shop as well. The virus sur-
vives in feather dust for long periods.
Polyomavirus
This is a widespread infection in Psittaciformes, but
was first called budgerigar fledgling disease (BFD).
Budgerigars have BFDV-1, the rest of the parrots BFDV-
3 (polyomavirus will also affect finches). Budgerigar
chicks can die in the first few weeks of life – either
suddenly, or with abdominal distension, subcutaneous
haemorrhages and ataxia. Some cases are more chronic
and develop dystrophic primary and secondary wing
feathers and tail feathers but do not die; this form is
more commonly seen in the UK. These cases resemble
PBFD. Other species of psittacine birds, when affected
by polyomavirus, can be very ill at weaning with non-
specific weight loss, anorexia, partial paralysis of the
gut, polyuria and watery droppings. They have a ten-
dency to haemorrhage easily, and may have CNS signs.
Not all the birds get the disease and not all of those
affected die; some (especially the older birds) recover to
become symptom-free carriers. Diagnosis using a PCR
test can be made using cloacal swabs or tissues from
post-mortem examination. A vaccine has become avail-
able in the USA.
Fungal diseases
Candida
This yeast infection is more commonly seen in birds kept
in high humidity and warm temperatures. It is more
common in birds being hand reared and kept in brood-
ers and in birds in tropical climates – it is a common
pathogen in Florida but less common in Yorkshire.
Affected birds develop caseous lesions in the commis-
sure of the beak, around the tongue and palate (Fig.
7.19) and the lining of the crop has the gross appear-
ance likened to a Turkish towel. Because the yeast
invades below the surface, ketoconazole and itracona-
zole are more effective treatments than nystatin and
amphotericin B.
Aspergillosis
This fungus invades the lungs and air sacs, and it is a
common cause of dyspnoea and weight loss in parrots.
It is more common in birds that are stressed, on a poor
diet, or in contact with large numbers of spores due to
a damp and dirty environment. It is frequently seen in
imported birds. Old and dirty travelling boxes are also
a source of this disease. Occasionally it invades the syr-
inx and causes dyspnoea and a loss of (or change in)
voice. Diagnosis is by radiography, which will show a
loculated appearance of the air sacs as well as densities
in the lung tissue. Confirmation using endoscopy and
Fig 7.19 The typical appearance of a parrot whose oral cavity is
infected with Candida. A smear made from the material coating the
palate showed masses of Gram-positive yeasts. The injury to the
commissures of the mouth is also typical of this disease. The bird has
been anaesthetized and intubated for this examination and for endoscopy
of the upper alimentary tract.

HANDBOOK OF AVIAN MEDICINE
164
culture is best. Treatment is time-consuming, involving
long-term dosage of itraconazole orally twice daily, and
nebulization three or four times daily with clotrima-
zole. It is necessary to continue the treatment for some
months. Some cases respond to oral itraconazole alone.
However, in many birds the prognosis is poor.
Syringeal aspergillosis cases should be referred to
an avian veterinary specialist; they are difficult to treat
because the blockage in the trachea has to be removed.
These cases also have a poor prognosis.
Some parrots, especially Amazons, develop Aspergillus
abscesses in the nasal passages; see ‘Sinusitis’.
Poisons
Lead
This is a very common poison in parrots. The bird
becomes unwell, goes off its food, becomes unsteady
on its legs and finally starts to convulse. Sources include
old (usually white) painted wood; soldered joints in old,
repaired cages; lead from windows and other sources.
Hard core (quarry-waste) used as a base for outside
aviaries may contain lead ores and has been seen as a
source of lead in Yorkshire parrots! The lead particles
are often seen on a radiograph (Fig. 7.15); grit is less
radiodense. Some cases are not obvious, and a blood
sample should be submitted to a laboratory. Much
of the lead is in the erythrocytes, so 0.5 mL of whole
unclotted blood should be sent in lithium heparin, not
in EDTA. Intramuscular injection of undiluted di-cal-
cium sodium edetate, is a low-risk, effective treatment
(0.25 to 0.75 mL). An intramuscular injection works as
well as an intravenous dose. Treatment should be given
to all cases where lead poisoning is suspected, even prior
to confirmation in doubtful cases. The dose should be
administered after taking the blood sample.
Teflon®
Over-heating non-stick pans, even for a short time,
causes the PTFE coating to depolymerize and form
highly toxic, volatile fumes. Birds in the same air-
space invariably die quickly after exposure with a dra-
matic pneumonia. Beware – some heat lamps are also
Teflon®-coated. There is no treatment.
Zinc
‘New wire disease’ is sometimes seen in birds that are
placed in newly meshed aviaries, and zinc toxicity may
be suspected in birds that become chronically unwell in
new cages. The diagnosis may be confirmed on blood
samples, but the blood tubes must not have rubber
stoppers or gaskets as some of these compounds con-
tain enough zinc to provide a false-positive result (this
should be checked with the laboratory in advance).
The source of zinc is either the white powdery coat-
ing found on the new wire (known as white rust), or
lumps of zinc galvanizing that are chewed off the wire.
Both cause zinc toxicity (Howard 1992). Zinc does not
remain in the body and is quickly removed once inges-
tion has stopped; there is no evidence that EDTA treat-
ment is useful. Lumps of metal in the gizzard should be
removed by endoscopic retrieval, by flushing the gizzard
under anaesthetic, or by surgical exploration of the giz-
zard through an incision in the proventriculus – these
cases should be referred! Washing the white rust off the
new wire with dilute acetic acid before introducing the
birds into a new aviary is preventative.
Diseases of the integument
As with dogs and cats the range of signs of skin disease
is limited, but the aetiologies for a particular set of signs
may be diverse.
Standard examination procedures apply: the bird and
its cage are observed. Is the patient the only inmate or is
there more than one bird? What signs is the bird show-
ing of skin disease? Is it pruritic; if so where and how
often is it irritated? Is there feather loss, if so have the
owners brought a feather? Is the bird bald because of
feather loss or failure to regrow feathers, or both? Are
there other signs of general illness: lethargy, inappetence,
PU/PD, etc.? Once this inspection is complete, remove
the bird from the cage and examine it conscious.
The head, beak and eyes should be examined first,
including a check inside the beak. Note any abscesses,
etc. (see vitamin A deficiency). Is the beak smooth and
shiny (usually abnormal) or is it covered with a fine
white powder (normal for most psittacine species)?
Each wing should be examined: spread the wing
fully and inspect it both dorsally and ventrally. Examine
feather stubs if they are chewed or cut short. Hold the
wing open and look through the feathers towards a
light: note any pinprick holes in the feathers through
which the light shines. Examine the down feathers on
the body under the wing: these are ‘powder down’
feathers (Fig. 7.1). Powder down is produced by the tips
of these feathers breaking free and forming a fine white
dust that is a feature of healthy parrot integument.
Pigeons, toucans, storks and herons also have powder
down, most other birds do not. Examine the feathers
and skin over the rest of the body, as well as the feet
and claws. The scaly skin should be supple and not be
crusty; the claws should be smooth, dry and sharply
pointed at their tips and there should be no discharge
from their base. The toes should flex and extend nor-
mally. Look at the entire integument, including the
preen gland. This is situated on the dorsal surface at the
base of the tail. It is poorly developed in parrots and is
totally absent in some families (such as Amazons and
pionus parrots). The function of the preen gland can

165
CHAPTER 7: PSITTACINE BIRDS
be checked by wiping a finger over the papilla; a nor-
mal gland will leave a greasy streak on the digit: under-
activity is common and these glands leave nothing at all
on your finger. Any enlargement should be viewed with
suspicion.
In many case it is rewarding to examine the bird
under anaesthetic. Look for external parasites: these
are very uncommon in parrots, and even less commonly
cause irritation or skin disease. If found, they can be
identified from the website www.federmilben.de – look
in the gallery. Examine broken or chewed feathers,
especially at the base where they enter the skin as this
can reveal pyoderma. Pluck a growing feather or two
for PBFD testing (full details under specific virus dis-
eases). Skin scrapings can be taken and are a useful way
of looking for fungi, yeasts, bacteria, etc. using cytology
and culture.
Some parrots get infection in their growing feathers.
This can be identified by a darker colour and abnormal
appearance of the follicles. It is useful to remove the
contents aseptically and confirm the presence of infec-
tion by cytology and culture of the contents.
Skin biopsies are not as useful as in cats and dogs,
since the integument is very fine, and even competent
dermatopathologists can fail to find signs of disease in
apparently grossly affected skin. However, if a biopsy
is needed, a full thickness of skin (NB: with no preop-
erative preparation) should be taken with scissors and
should include some normal and abnormal feather folli-
cles. Multiple biopsies should be obtained and spread on
paper or pinned to a wooden tongue depressor with 25-
gauge hypodermic needles; then fixed in formol saline
by floating the paper/wood with the skin immersed in
the fixative. Usually the skin deficit is sutured using
fine soluble suture material. Biopsies should be taken
from specific lesions or skin on the trunk of the body,
remembering that the feathers grow from specific areas
(feather tracts) separated by areas of skin with no feath-
ers. Do not remove any major feather follicles from the
wing or tail, as these feathers cannot regrow.
Lateral and ventrodorsal radiographs are useful to
rule out internal disease such as air sacculitis, abscesses,
liver disease, etc. A blood sample may do the same.
Internal disease may cause birds to chew the area of
their body over the internal lesion; these areas are not
bilaterally symmetrical, see below.
Bald birds
Feather loss on the head is rarely self-inflicted. Some
birds can be made bald by over-zealous head preening by
a ‘loving’ mate (common in Pionus spp.). Occasionally
birds become bald by fighting with other birds, but other
lesions are usually evident in such cases. Soft food may
become matted to the facial feathers in adults or young-
sters being reared, and this will cause a skin infection.
The mat and feathers will be shed, leaving patches of
feather loss around the face.
It is important at the outset to rule out circovirus as
a cause of feather loss. Cases where there is a loss of
powder down, low white blood cell count (especially
in grey parrots), feathers that have died during growth,
birds with beak abnormalities, and birds that have had
contact with potential or known carriers of circovirus
should be tested.
Feather picking or plucking is a common problem
in parrots, especially grey parrots, cockatoos, cocka-
tiels and macaws. These are nearly always hand-reared
birds, even when imported, and they are usually socially
deprived (kept on their own) and hormonally active
(more often presented at the start of the breeding sea-
son). The birds are first presented appearing to be irri-
table with parts of their integument, pulling violently at
their claws or feathers. They may start chewing at the
cut base of their clipped wing feathers, or even chew
off normal tail and wing feathers. They may decide to
pull contour feathers out completely; common sites
are around the neck and over the shoulders, under the
wings on the body, and down the back. The feather-
plucking bird often produces bilaterally symmetrical
lesions. Some birds, especially cockatoos and lovebirds,
will mutilate themselves so badly that they will chew
through the skin into the subcutis and even into muscle.
These birds should be checked for circovirus as this may
be an underlying factor that will prevent recovery. Some
birds, such as conures, will pull out or chew off their
feathers when stressed by an environmental change; this
may happen when the bird is admitted as an inpatient,
which is embarrassing for the veterinarian.
Many feather-plucking birds have higher levels of
(faecal) corticosterone than normal; this is an indication
of increased levels of stress (Owen & Lane 2006).
Occasionally unilateral bald areas are produced.
These should be investigated as they may be indicative
of internal disease in that area. Amazon and pionus par-
rots can be affected by behavioural problems too, but
seldom pluck their feathers right out. They will ‘scis-
sor’ off parts of feathers, or appear much more irritated
with their integument and will chew the skin on their
legs violently; use their feet to scratch violently at their
flanks; hang on their cage bars and rub their bodies on
the cage as if very irritated by some skin problem. Again
this is seen in birds that are hormonally active and
socially deprived and it is more common in hand-reared
birds. As with grey parrots, mites are exceedingly rare
and are unlikely to be the cause of these signs.
Many cases where parrots are feather plucking are
incurable, but some respond well. Treatment for feather
pluckers should include dietary advice and environ-
mental enrichment with toys and tree branches, etc.
Companionship may be very useful if the patient is able
to recognize and therefore respond to another bird.

HANDBOOK OF AVIAN MEDICINE
166
In many cases the bird is so strongly imprinted on
humans that it fails to recognize other parrots. The
owner should be discouraged from too much sensual
physical contact with the bird (e.g. stroking of neck or
rump), as this reinforces the problem. It is very difficult
to replace the social interaction seen in a flock of par-
rots within a captive pet environment.
Hormonal suppression can work in some cases, but
progestogens will cause polyphagia and polydipsia and
may well exacerbate occult metabolic problems. Drugs
used for behavioural problems in humans can be use-
ful. Diazepam in the drinking water (3 drops in 30 mL
of water), haloperidol (0.4 mg/kg) or fluoxetine (Prozac)
(1 mg/kg) have all been suggested. In some cases the
medication is required at times of maximum hormo-
nal influence and in other cases it is for life. However,
prescribing these drugs should not be a first line of
treatment for every plucking bird: all cases should be
thoroughly investigated for possible causes.
Pruritic birds
External parasites are very uncommon in parrots,
except for Cnemidocoptes pilae that causes ‘scaly face’
in budgerigars. These mites live in tunnels in the epider-
mis and cause considerable skin thickening (Figs 7.20A
and B). The mite can easily be killed with an injection
or oral dose of ivermectin (200 g/kg), repeated after
2 weeks. Red mites can cause problems in aviary birds
and, occasionally, pet birds. The mites are only active at
night, and the birds chew their legs. Mite control may
be necessary on the birds, but the environment must
also be treated. Fipronil (Frontline Spray, Merial) is
very effective; a squirt under each wing usually removes
external parasites such as mites and lice. Feather lice
and mites in birds tend to be species-specific, and as
such are uncommon on parrots in the UK – presumably
when they have been removed there is no reservoir from
which they can return.
Most pruritic parrots have some definable behav-
ioural problem, a pyoderma, or internal disease such as
hepatitis, air sacculitis or an internal abscess.
Pyoderma
Areas of thickened, sore and crusted skin may be due
to a pyoderma. Bacteriology, cytology and skin biopsy
are all required for a definitive diagnosis. Appropriate
antimicrobial therapy is required, often for some weeks
or occasionally months. Attention must be paid to
selecting the correct antibiotic: drug sensitivity of the
pathogen, method of drug administration and the phar-
macodynamics of the drug must be integrated for suc-
cessful results. If the lesion is not resolving in spite of
adequate treatment, the bird may have a behavioural
problem.
The beak may also become infected; this is more usu-
ally caused by poor nutrition and trauma than by a pri-
mary pathogen. The virus causing psittacine beak and
feather disease is the exception, and degenerative lesions
in the beak and claws are highly suspicious of this dis-
ease (Fig. 7.21). A PCR test should be performed to
look for the virus in all birds showing degenerative beak
lesions. Dermatophytes are also able to infect birds, and
these usually give a very crusty appearance. Again a
scraping (or cytology and culture) is required. It can be
difficult to know if some fungi are a secondary problem
or primary pathogens. Aspergillus and Candida should
be viewed with suspicion as primary pathogens in the
B
Fig 7.20B The same bird after 4 weeks. It had received two injections 2
weeks apart. This budgerigar has the typical feathers of an adult ‘normal’
bird; compare with Figure 7.2.
A
Fig 7.20A A budgerigar showing the typical appearance of
cnemidocoptic mange. The bird was injected with ivermectin.

167
CHAPTER 7: PSITTACINE BIRDS
UK, as they are not encouraged to grow in our colder
and less humid climate (unlike in most of the USA).
Xanthoma
Thickened yellow skin can occur in any permanently
featherless area as a normal reaction of the body, but
occasionally birds are presented with a massively swol-
len, thickened area of yellow skin (see Figs 3.31 and
3.32). This requires surgical intervention.
Feather damage and defects
The normal feather should be able to maintain its
structure with routine preening from the bird. The
barbules should all be interlocked, giving the feather
a firm and unbroken appearance. The growing quills
should emerge from the sheath and the sheath should
fall away, allowing the feather to unfurl and form
a normal shape; the colour of the feather should also
be normal. Nutritional defects are a common cause of
feather problems. Seed is deficient in sulphur-containing
amino acids, and this will give very poor quality feath-
ers, as will a lack of essential fatty acids: the feathers
have poor colour, the barbules separate and the feather
fails to lock into its correct shape. In birds that are not
allowed to bathe or are not sprayed, dirt will build
up in the feather’s structure causing similar problems.
Many birds on a poor diet become thyroid hormone
deficient, and this results in failure to moult and grow
new feathers. Always check with the owner when the
bird moulted last – did it change all its feathers, have
they grown in normally? A parrot should have a bloom,
or fine covering of powder down.
Feathers may be found showing bands of differ-
ing colour. This is usually due to dietary change or
ill health whilst the feather was growing, and may be
mirrored by a line of changed keratin in the beak.
Breaks in nutrition in growing feathers will cause lines
of weakness (fret marks or stress bars). These are usu-
ally seen in young birds and occur in all the feathers
that are growing, causing a line of weakness across
all the tail or wing feathers. Fret marks can be found
in isolation on feathers, and in these cases are usually
formed by quill mites (Syringophilus spp.) which have
eaten part of the growing feather when it was curled up
in the erupting sheath. These mites are very difficult to
demonstrate: look in a KOH-cleared squash preparation
from the mid-third of the growing feather shaft of an
affected feather. This mite seems to affect young birds
more frequently than adults.
Beak and claw diseases
The beak can be injured by another bird. If the upper
beak is bitten off completely then it is impossible to
replace; the best that can be achieved is the produc-
tion of a fibrous pad after granulation, and these birds
manage surprisingly well. Small holes through the beak
or injuries from flying into wire mesh will heal with
antibiotic therapy and good husbandry. Macaws are
prone to developing beak deformity whilst growing and
young birds can be presented with the upper beak twist-
ing to one side. Cockatoos become ‘undershot’ with
the upper beak bending ventrally and going inside the
lower beak, rather than outside. These cases should be
corrected, and are easiest to do while the bird is still
growing. There are several specialist techniques for
doing this.
Loss or injury of a normal claw or the end of a digit
is usually made good by the bird itself as it will often
chew the digit back to healthy tissue. However, birds
are sometimes seen with dry gangrene of the digit or a
bitten, mangled toe. The bird should be anaesthetized,
the digit amputated to healthy tissue, and the skin
sutured with fine, soluble suture material. The surgical
site should be kept clean, dry and open to the air and a
5-day course of antibiotic should be given.
The virus responsible for psittacine beak and feather
disease is common; full details of its effects are given
under ‘Infectious viral diseases’, but changes will be
found in the beak and claws.
Fig 7.21 Degenerated beak in a cockatoo with advanced PBFD.

HANDBOOK OF AVIAN MEDICINE
168
References
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of Avian Veterinarians 7(1):31–33
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Forshaw J M, Cooper W T 1973 Parrots of the world. Lansdowne Press,
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plucking parrots (Psittacus erithacus). Veterinary Record 158:804
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Further reading
Members of the parrot family:
Collar N J 1997 Psittacidae (parrots). In: Handbook of birds of the world,
Vol IV, Sandgrouse to cuckoos. Lynx edicions, Barcelona, p 280–477
Rowley I 1997 Cacatuidae (cockatoos). In: Handbook of birds of the world,
Vol IV, Sandgrouse to cuckoos. Lynx edicions, Barcelona, p 246–279
General husbandry and breeding:
Low R 1992 Parrots, their care and breeding. Blandford/Cassell, Poole,
Dorset
Budgerigars:
Moizer S 1988 Budgerigars: a complete guide. Merehurst Press
Feeding birds and their responses:
Carey C (ed) 1996 Avian energetics and nutritional ecology. Chapman &
Hall, New York
Stanford M 2005 Nutrition and nutritional disease. In: Harcourt-Brown N,
Chitty J (eds) BSAVA Manual of psittacine birds, 2nd edn. BSAVA,
Cheltenham, p 136–154