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Redshanks and other breeding waders of British saltmarshes
Abstract
See page 37 of scanned copy ISBN 0 903 138 26 3
... For each of the four species, estimates of the numbers of breeding pairs at each subsite were determined following recognised speciesspecific methods. The methods used were as follows: lapwingthe maximum count of individuals during visits 1-3, divided by two (O'Brien & Smith, 1992); curlewthe mean count of individuals during visits 2 and 3, multiplied by 0.71, plus 0.1 (Grant et al., 2000); redshank the mean count of individuals recorded before 21 May (by the end of visit 2; Cadbury et al., 1987); snipethe maximum number of drumming or chipping birds recorded during any one visit (O'Brien & Smith, 1992). For lapwing, curlew and redshank, flocks of more than four individuals were excluded from the above calculations, as these were considered likely to be non-breeding (Colhoun et al., 2015). ...
... On the other hand, formerly favourable meadows that were characterized by a great floristic diversity and a heterogeneous vegetation structure have gradually been converted into a monospecific, fertilized sward, which is sometimes too dense to allow birds to feed in (Butler & Gillings 2004, Devereux et al. 2004, McCracken & Tallowin 2004, Eglington 2008. In addition, the homogenization of the vegetation structure and the simplification of plant communities have contributed to rarefaction in arthropods as well as to a reduction in their overall size (Kajak 1978, Green & Cadbury 1987, Siepel 1990, Blake et al. 1994, Vickery et al. 2001, McKeever 2003. In this context, smaller prey have become less profitable (in terms of energy gained per arthropod consumed) and therefore have increased the difficulty for adults and chicks to meet their energy needs. ...
Like most shorebirds in Europe, breeding populations of Eurasian curlew (Numenius arquata) are suffering from habitat loss and degradation mainly caused by changes in agricultural practices. In Deux-Sèvres (France), the number of pairs has gradually declined since the early 2000s in the main, historical breeding site, while a new breeding site has appeared recently 80 kilometres further north with increasing number of pairs through the survey period. Many wheat fields and rare dry grasslands are found in the north, whereas the landscape in the south is mainly composed of tillage plots, hay meadows, and pastures. This study aims to highlight differences in food availability and quality between the two areas. Sample series of ground-dwelling and vegetation-dwelling invertebrates were carried out during three key stages of the species breeding cycle with pitfall traps and sweep nets. Dry grasslands in the north were found to be the most favourable habitat in terms of prey availability for adults and for chicks during the brood-rearing period. Moreover, hay meadows and pastures in the south seemed to be resource-abundant feeding habitats. Therefore, the habitats of the northern site seem to offer a greater abundance of invertebrates and thus a potentially larger food resource than the southern one. It follows that the northern site likely offers better breeding conditions, especially for the growth of chicks. An increase in the area of dry grasslands in the north and the establishment of adapted agricultural management in the south would be favourable for the conservation of local curlew populations.
... Although Redshank breed in various grassland habitats, saltmarshes are internationally important for the species (Reed, 1985;Cadbury et al., 1987;Brindley et al., 1998). In Britain, saltmarshes once held around half of the national breeding population , but the number of Redshank breeding on British saltmarshes declined by >52% between 1985 and 2011 (Malpas et al., 2013b). ...
... Great Britain supports internationally important breeding numbers of Common Redshank Tringa totanus, with over 18% of northwest Europe's estimated 100 000-172 000 breeding pairs (Piersma 1986, Batten et al. 2010. Redshank breed in various habitats, but saltmarshes hold approximately 50% of the British breeding population , making British saltmarshes both nationally and internationally important for the species (Cadbury et al. 1987. Recent surveys of British saltmarshes found a 52.8% reduction in nesting pairs between 1985 and 2011 and highlight the failure of conservation management to reverse historical Redshank declines (Malpas et al. 2013). ...
The Common Redshank Tringa totanus breeding population on British saltmarshes has declined by over 50% since 1985, with declines linked to changes in grazing management. Conservation initiatives have encouraged low-intensity grazing of below one grazer per hectare, but Redshank have continued to decline, even in regions where light grazing was predominant. This study quantified effects of grazing intensity on Redshank nest survival over six lightly grazed saltmarshes with livestock densities between 0 and 0.82 cattle per hectare, in the Ribble Estuary, north-west England. We assessed whether grazing resulted in nest mortality either directly, through cattle trampling, and/or indirectly through grazer modification of habitat that accelerates predation risks. Cattle density was recorded both during the Redshank breeding season and for one year prior to the study, to account for both short-term trampling effects and the longer term effects on vegetation. Results showed that risk of nest loss to trampling increased from 16% at 0.15 cattle per ha to 98% at 0.82 cattle per ha in the breeding season. The risk of a nest being predated increased from 28% with no grazing to 95% at 0.55 cattle per ha based on all year grazing data. These results suggest that even light conservation grazing at less than one cow per ha can reduce Redshank nest survival rates to near zero. It may therefore be appropriate to reduce saltmarsh grazing intensities further, or change the timing of saltmarsh grazing to reduce the number of livestock present during the Redshank breeding season.This article is protected by copyright. All rights reserved.
... This ensured that data were analysed in a comparable way for each of the three surveys. Correction factors used for estimating numbers of Snipe (Green 1985), Curlew (Grant et al. 2002) and Redshank (Cadbury et al. 1987) were not used since these rely on calibrated population estimates, which would not be possible to map. Population density estimates for Snipe and Redshank in particular, therefore should be considered conservative. ...
... Curlew: (maximum number of individuals) × 0.71 with 0.1 added for each site on which the species is found (Grant et al. 2000). Redshank: mean count of individuals between late April (24th) and 31 May (Cadbury et al. 1987). ...
Capsule Lapwing, Snipe, Curlew and Redshank decreased significantly between 1982 and 2002,
while over the same period Oystercatcher increased.
Aims To provide current status and population trends for waders breeding on lowland wet grassland in
England and Wales.
Methods Waders were counted and mapped on three visits to 1051 lowland wet grassland sites,
between April and June 2002. Data were compared with those gathered using identical methods in a
survey in 1982 and related to land use characteristics and conservation designation.
Results Between 1982 and 2002 there were significant declines of 38% for Lapwing Vanellus vanellus,
61% for Snipe Gallinago gallinago, 40% for Curlew Numenius arquata and 29% for Redshank Tringa
totanus. Oystercatcher Haematopus ostralegus increased significantly by 47% in the same period.
Populations of all species were highly aggregated with most of the birds found on a small number of key
sites. Site designation was found to be an important predictor of breeding wader distribution, density and
density change.
Conclusions The marked population declines of four grassland wader species over the last 20 years
are of considerable concern. Careful management of nature reserves and other key sites is essential to
halt these declines, while wider scale and more carefully targeted agri-environment schemes may hold
the key to reversing declines in the longer term. The efficacy of site designation and current
agri-environment schemes for conserving breeding waders on wet grasslands needs to be reviewed.
... Redshank have shown no change in breeding numbers on lowland grasslands since 1982, The easterly distribution noted by Smith2 was still apparent and has also been noted in the distribution of Redshank on saltmarshes. 13 Almost 70% of all lowland grassland Redshank were in the Southern and Anglian regions. Table 4 shows change in numbers of waders in relation to different levels of site protection. ...
A randomly selected sample of sites surveyed in 1982 for the Breeding Waders of Wet Meadows survey was re-visited in 2989 and information on numbers of breeding waders collected. This showed that over this period numbers of Lapwings Vanellus vanellus had declined significantly by 38%, whilst Oystercatchers Haematopus ostralegus had increased by 56%. There was no evidence of a change in numbers of Snipe Gallinago gallinago, Redshank Tringa totanusor Curlew Numenius arquata. In both 1982 and 1989 a high proportion of all Snipe and inland breeding Redshank occurred on nature reserves. Numbers of Snipe and Redshank (but not Lapwing) were less likely to have declined on reserves than on unprotected sites.
We report the results of two surveys of the same sample of 77 saltmarsh sites around the coast of Great Britain, conducted in 1985 and 1996 to estimate breeding abundance and the conservation status (i.e. stable, increasing or declining) of redshank Tringa totanus nesting on saltmarshes. The 1985 estimate was 21 022 pairs (confidence limits: 14 941–26 818 pairs) and the 1996 estimate was 16 433 pairs (confidence limits: 11 291–21 943 pairs). Saltmarshes, therefore, support c. 45% of the population of redshank breeding in Great Britain. We present evidence to show that these abundance estimates are unlikely to be biased as a result of poor regional or habitat coverage by the sample of sites surveyed. Comparison of breeding density changes within survey sites between 1985 and 1996 showed a significant mean decline of 10.98 pairskm−2 (confidence limits: 4.68–16.83 pairskm−2). This represented a loss of 4807 breeding pairs, i.e. a 22.9% decline in abundance. We suggest that conservation measures are needed, including the use of habitat creation for breeding redshank. A national assessment of the impact of current grazing practices on nesting redshank is also required as the basis for assessing which grazing practices are currently a threat, and of agricultural policy or conservation management measures to mitigate these.
The results of a long-term capture-mark-recapture ringing programme carried out on a coastal population of breeding Redshanks Tringa totanus between 1974 and 1988 are presented.
Both sexes were equally likely to be recaptured in subsequent years, as were birds captured for the first time compared with those that had been captured previously. Older birds were more frequently recaptured than were young birds. There was no significant difference in male and female adult survival rates, with a mean of 72% of females and 75% of males surviving each year.
The breeding population fluctuated annually with estimated breeding densities of 122–285 pairs per km2. Variation in breeding numbers (males), but not survival, was partially attributable to winter air temperature.
1. Invertebrates were collected, using corers and sweep nets, from 25 salt marshes, and adjacent mudflats and strandlines, in Essex, eastern England, to describe assemblages and assess their conservation importance.
2. Sweep net samples were more variable in taxon richness than core samples. Neither sampling method, nor samples from the three habitats (main marsh, mudflat, strandline) could be used as an indicator of taxon richness of the salt marsh as a whole.
3. Core samples collected relatively few, but often abundant, marine species which were generally widespread and a large number of terrestrial species, which were generally restricted in distribution. The mudflat fauna was species poor. Sweep net samples of main marsh and strandline were markedly different in their species composition; many species, with generally patchy distributions, were recorded and Diptera predominated. There was no relationship between invertebrate taxon richness, plant species richness or measured environmental variables.
4. TWINSPAN was used to classify sites and invertebrate species. On the entire data set, six groups of sites were identified, but there was no trend in taxonomic richness. Only 25% of species were restricted to a single group. Sweep nets provided a much higher discrimination of sites.
5. The conservation value of salt marsh sites for invertebrates is discussed using four criteria: community distinctiveness, species richness, species rarity and community functioning. A holistic approach to the conservation of salt marshes within the region is recommended.
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