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Citations
... The introduction and subsequent establishment of the red fox (Vulpes vulpes) across much of continental Australia and some offshore islands has led to the decline and extinction of native fauna species, while also imposing negative economic impacts on the agricultural industry (Dickman 1996;Gong et al. 2009;Woinarski et al. 2015). To address these issues, management programs have been implemented across Australia, employing various control measures such as trapping, shooting, den fumigation, and baiting with sodium monofluoracetate (1080) (Saunders et al. 1995;Kinnear et al. 1998;Saunders and McLeod 2007;West and Saunders 2007;Read et al. 2019). Trapping, shooting and den fumigation can be highly target specific but are generally labour-intensive, limiting their application to small-scale situations and reducing their potential for sustained impact mitigation (Saunders et al. 1995;Saunders and McLeod 2007;Newsome et al. 2014). ...
Context
Canid-pest ejectors (CPEs) offer a compromise between broadscale free-baiting programs that can have non-target impacts and more target-specific methods such as trapping and shooting, which are inefficient across larger scales. CPEs target wild canids, such as red foxes (Vulpes vulpes) and wild dogs (Canis spp.). However, there are situations where red fox control is required, but the risk to non-target canids, such as dingoes and other dogs, prevents the use of broadscale baiting.
Aims
We field-trialled and refined a collar for the CPE that was designed to allow red foxes to trigger CPEs, but prevent dingoes and medium–large-sized dogs from doing so.
Methods
We deployed uncollared and collared CPEs paired with camera-traps across two study areas in central Australia, and assessed which taxa triggered CPEs and whether the activity rates, behaviour and CPE triggering rates of five taxa (red foxes, wild dogs, feral cats (Felis catus), corvids (Corvus spp.), and varanids (Varanus spp.)) differed between CPEs with and those without collars.
Key results
With a simple modification to our original collar design, a red fox was able to trigger collared CPEs. Collared CPEs were triggered by wild dogs when they were set with the bait head 1 cm below the rim of the collar, but not when they were set with the bait head at 2 cm below the rim. Uncollared CPEs were triggered by wild dogs (97.03% of triggers), red foxes (1.98%) and corvids (0.99%). Activity rates of the study taxa towards CPEs did not differ between collared and uncollared CPEs. However, behavioural analyses suggested that red foxes and wild dogs showed more caution around collared CPEs.
Conclusions
We present proof-of-concept that deploying CPEs inside a collar increases the target specificity of this device by excluding wild dogs, while allowing red foxes to access the bait head. However, our data suggest that the addition of a collar may reduce interaction rates of red foxes and wild dogs with CPEs.
Implications
The collared CPE provides a control method for red foxes that reduces the risk to dingoes and other medium–large-sized dogs and may allow for greater landholder participation in red fox management.
... The use of meat-based baits (chicken wings, red meat) impregnated with 1080 is currently the most widespread and effective method of fox control in Australia (West and Saunders 2007;Mahon 2009). Hence, on 24 October 2017, we began supplementing CPEs with fresh chicken wings injected with 1080, distributed across 196 bait sites (Fig. 2). ...
Context. The introduced red fox has driven the decline or extinction of numerous wildlife species in Australia, yet little information exists on the population densities of foxes in most ecosystems. Fox monitoring programs will differ widely depending on the goals of management, which, in turn, will determine whether the appropriate metric is a density estimate, or some proxy thereof, and the time and resources required.
Aims. This study aims to assist wildlife managers to design fit-for-purpose monitoring programs for foxes by providing a better understanding of the utility and precision of various monitoring methods.
Methods. We surveyed foxes monthly over four consecutive years in a semi-arid region of Australia by using sand plots, camera traps and GPS telemetry. The resultant data were used to produce population estimates from one count-based method, two spatially explicit methods, and two activity indices.
Key results. The incorporation
of GPS-collar data into the spatial capture–recapture approaches greatly reduced uncertainty in estimates of abundance. Activity indices from sand plots were generally higher and more variable than were indices derived from camera traps, whereas estimates from N-mixture models appeared to be biased high.
Conclusions. Our study indicated that the Allen–Engeman index derived from camera-trap data provided an accurate reflection of change in the underlying fox density, even as density declined towards zero following introduction of lethal control. This method provides an efficient means to detect large shifts in abundance, whether up or down, which may trigger a change to more laborious, but precise, population monitoring methods. If accuracy is paramount (e.g. for reintroduction programs) spatially explicit methods augmented with GPS data provide robust estimates, albeit at a greater cost in resources and expertise than does an index.
Implications. Our study demonstrated that the shorter the survey period is, the greater is the likelihood that foxes are present but not detected. As such, if limited resources are available, longer monitoring periods conducted less frequently will provide a more accurate reflection of the underlying fox population than do shorter monitoring periods conducted more often.
... Islands are biodiversity hotspots and eradication of invasive species, such as feral pigs, is often necessary to prevent extinctions of native species (Hutton et al. 2007;Buxton et al. 2016;Holmes et al. 2019). Internationally, management of pig populations commonly uses poison baiting, trapping, aerial and ground shooting (Reddiex et al. 2006;West & Saunders 2007). Strategic eradication programmes utilising multiple techniques have made feral pig eradications possible on islands as large as Santiago Island, Galápagos Islands, Ecuador (58 465 ha; Cruz et al. 2005). ...
A feasibility study for removing feral pigs (Sus scrofa) from Auckland Island trialled feeders monitored by trail cameras to determine their effectiveness for detecting and attracting feral pigs. Ten automatic feeders were installed during January–February 2019 (summer) and again in August–September 2019 (winter) on Auckland Island. They delivered kibbled maize daily for a period ranging from 25 to 37 days. Sites selected for feeder installation needed to be of appropriate relief and area to allow feeder and trap installation, as would occur during an eradication operation. Feeder success varied across sites during the trial. Site selection where there was evidence of fresh pig presence improved the rate of visitation. Feeders offer significant efficiencies to lethal techniques such as trapping by automatically dispensing feed to allow constant supply over a long period. This automation reduces operator effort, but is also advantageous as consistent feed times train pigs to condition their visits so they can be more effectively targeted. In this trial, most visiting pigs returned to the feeder daily from around 15 days after installation. Automated feeders will be an integral component of the proposed methodology for Auckland Island pig eradication to target nocturnal individuals and family groups, and, importantly, reduce the risk of education through non-lethal engagement.
... Islands are biodiversity hotspots and eradication of invasive species, such as feral pigs, is often necessary to prevent extinctions of native species (Hutton et al. 2007;Buxton et al. 2016;Holmes et al. 2019). Internationally, management of pig populations commonly uses poison baiting, trapping, aerial and ground shooting (Reddiex et al. 2006;West & Saunders 2007). Strategic eradication programmes utilising multiple techniques have made feral pig eradications possible on islands as large as Santiago Island, Galápagos Islands, Ecuador (58 465 ha; Cruz et al. 2005). ...
... The most commonly used methods to reduce feral pig population densities are poison baiting, trapping, and shooting from the air or ground (Reddiex et al. 2006;West & Saunders 2007). Best-practice guidelines recommend that several control tools or methods should be integrated into management programmes because some proportion of the population will generally be insusceptible to any given control method (e.g. ...
... Ballari et al. 2015;Centner & Shuman 2015;Massei et al. 2015). Pig hunting with firearms or dogs and knives is a popular recreational activity in many parts of Australia and is viewed by many hunters and some land managers as a useful pig control tool (Reddiex et al. 2006;West & Saunders 2007). Until the recent registration of sodium nitrite as a toxicant, most feral pig control in New Zealand was limited to hunting. ...
Introduction Feral pigs (Sus scrofa L.) are widely regarded as one of Australasia’s most destructive pest animals. They inhabit a large proportion of both Australia and neighbouring New Zealand. They can cause severe damage to a wide range of agricultural, biodiversity, and environmental resources. Private landholders, government agencies, and other authorities carry out many feral pig control programmes each year. However, pigs are also highly valued by some sections of the community for hunting or commercial exploitation. Although wild or feral pigs are widely distributed across the globe (Long 2003), the Australian situation is in many ways unique. There has been a long history of active feral pig management in Australia and, in contrast to New Zealand, Europe, and the Americas, wild-living pigs are consistently recognized and treated as a pest in all onshore jurisdictions. Conversely, the most widely used methods and tools for controlling feral pigs in Australia are uncommon elsewhere. This chapter will review the origin and distribution of feral pigs across Australia and New Zealand, their destructive impacts, useful values, and their management and control. It will highlight current and future challenges to the effective mitigation of pig impacts, and propose possible solutions. At a fine scale, some of these challenges may be peculiar to the region, but the broader trends and pressures from which they emerge are common to many regions of the globe where wild-living pig populations conflict with human values. Trends in Abundance and Distribution Notwithstanding speculation of a pre-colonial origin for wild-living pigs in some parts of north-eastern Australia (Baldwin 1983), the first known introduction of pigs onto the Australian continent occurred with the arrival of at least 48 animals with the first European settlers in 1788. While other livestock failed to thrive, free-roaming pigs increased rapidly and soon became such a pest to the fledgling colony’s food supply that orders for their control were issued within seven years of settlement (Robertson 1932). The subsequent declaration of a series of increasingly dire control orders suggests that the first attempts at regulation to manage damage caused by pigs were not very effective.
... Many control methods have been used in efforts to reduce the environmental and agricultural impacts of foxes. These include poison baiting, ground shooting, use of guardian animals, trapping, den fumigation, fox drives and trapping (West and Saunders 2007;Saunders et al. 2010). Currently, the most widespread method of control across large areas in Australia is poison baiting, and this is also considered the most cost effective method available (Saunders and McLeod 2007;Saunders et al. 2010). ...
Context The European red fox (Vulpes vulpes) is subject to control by poison baiting in many parts of its range in Australia to protect both native and domestic species. Assessments of baiting programs can improve their effectiveness and help ensure that long-term control outcomes are achieved. Aims We describe spatial and temporal patterns of bait uptake by the red fox in remnant forest within an agricultural matrix, including multiple bait-takes and hotspots of activity over time, and examine the response of foxes to baiting operations. Methods We analysed bait uptake (Foxoff®) from 12 baiting operations over 5 years in the Goonoo forest, a 62500ha remnant surrounded by cleared land in central New South Wales, Australia. More than 8000 checks of bait-stations were analysed to provide indices of fox activity per bait-check, patterns of bait removal during bait-checks, and bait uptake at stations within and across operations. Fox activity was also assessed before and after four operations using sand plots. Key results There was no consistent decline in relative fox activity in relation to changes in bait-take; increases in the activity index occurred in successive checks within most operations. Spatial analyses of checks within control operations showed that consecutive baits were removed at more than 70% of bait stations that were visited by foxes. Temporal analyses showed further that within an operation, multiple bait-takes occurred at ∼20% of stations and, across all operations, hot spots of activity could be identified. Conclusions A short (2-week) baiting window in standard baiting operations may not be effective in reducing the activity of foxes across the landscape. It is likely that many baits are being cached during each operation, and that foxes move into the baited area from unbaited surrounding areas. Implications More frequent and timely baiting operations are needed to achieve maximum disruption to the fox population in the remnant forest environment, at least as indicated by patterns of bait-take. Increasing the distance between baits, to ∼1.5km, while reducing baiting-gaps at the landscape scale, will also be important to reduce caching and still ensure that baits are encountered.
... Massei et al. 2015). In Australia, shooting has been a popular method for controlling a wide range of pest animals , West & Saunders 2007. ...
... It is, therefore, often difficult for managers to accurately predict the likely value of ground-based shooting as a pest control tool for any given situation, and therefore to determine how it might best be integrated into, or left out of, strategic pest management programs. In many cases, the choice to use shooting as a control tool seems to be based on practical or political convenience, or simply because there seems to be no other option available except doing nothing (Rutberg 1997, West & Saunders 2007. Nonetheless, the use of ground-based shooting as a pest control tool appears to be increasing in many parts of Australia. ...
... Nonetheless, the basic typology provides a useful construct for evaluating the effectiveness of shooting operations as a pest control tool. Currently, ground shooting is used in programs aiming to control wild dogs (Canis spp.), foxes (Vulpes vulpes), cats (Felis catus), rabbits (Oryctolagus cuniculus), pigs (Sus scrofa), goats (Capra hircus), deer (Cervidae), macropods and native waterfowl (Grigg, 1995, Bomford & Sinclair 2002, West & Saunders 2007. It is not possible to estimate the relative importance of different types of shooting operations to the control of each of these species. ...
Ground-based shooting is commonly used to try and reduce the impacts or abundance of over-abundant animal populations in many parts of the world. It encompasses a wide range of activities carried out by many different types of people driven by a variety of interacting motivations. Given this contextual complexity, it is unsurprising that results of ground shooting operations for pest animal control range from counter-productive to highly effective.
This review systematically examines a sample of published papers that report on the efficacy of ground-based shooting operations in Australasia, North America, Europe and Japan. Although the sample was small and the literature surveyed included many flaws and inconsistencies, several key themes that contribute to effectiveness were identified. These included: 1) the use of tools or methods that enhance efficiency; 2) a manageable geographic area of operations; and 3) the use of highly skilled and committed shooters. Factors repeatedly shown to detract from efficacy included: 1) the inability of harvest-oriented shooters to sustain effort as target populations declined; 2) insufficient spatial or temporal coverage to counter immigration; and 3) the presence of refugia within treatment areas.
It is clear that ground shooting can make important contributions to the management of pest or over-abundant species, but shooting alone is often insufficient or prohibitively inefficient to achieve desired outcomes. Managers planning to use ground shooting as part of a population management strategy should: 1) carefully examine the options to determine what type of shooting operation is likely to be most useful; 2) establish and monitor meaningful objectives; 3) ensure that operations are sufficiently resourced to meet and maintain those objectives; and 4) integrate ground shooting with other control methods wherever possible. Operations that are poorly-planned, resourced, integrated and executed are unlikely to deliver useful outcomes. Ground-based shooting is rarely, if ever, a cheap and easy method for reducing pest impacts or abundance.
... Live trapping has been one of the most common forms of feral pig control used by conservation organisations, government bodies, and private landholders (Reddiex et al. 2006, West andSaunders 2007). Unlike the U.S., neck snares are not permissible in Australia. ...
... This high-level planning and prioritisation has facilitated research that has described the distribution and relative abundance of feral pigs at national and regional scales (e.g., West and Saunders 2007), identified and mapped high-value sites where feral pigs co-occur with susceptible species or ecosystems at national and statewide scales (Anonymous 2010), improved our understanding of some of their impacts (e.g., Mitchell 2010), broadened the range of control methods available to reduce pig impacts and numbers (e.g., Lapidge et al. 2012), and elucidated the roles of different social and economic factors that can influence the efficacy of feral pig management (e.g., Gentle and Pople 2013, Koichi et al. 2013). Importantly, it has also provided targeted funding for on-ground management and control programs to reduce specific, high-priority threats, such as aerial shooting programs to reduce predation on marine turtle nests. ...
Feral or free-ranging pigs have been a problem in Australia since the first years of European settlement, and they now occur in a wide range of habitat types throughout much of the continent. Feral pigs impact environmental, agricultural, and cultural resources, but they can also have commercial value from harvesting and recreational or subsistence hunting. It has been difficult to quantify many of the adverse impacts of feral pigs. Consequently, most management programs aim to mitigate actual, potential, or perceived impacts that have been inferred from observational studies and anecdotes, untested retroductive hypotheses, or observations generated from outside of Australia. Lethal control to reduce population density is the most common form of management, and it is often applied as a form of insurance, rather than to mitigate specific, measurable impacts. We suggest that future management programs should aim to quantify the effects of management actions on pig populations and the vulnerable resources that are the basis of real management objectives. There are important ethical and practical reasons for this approach, which should in turn enhance the efficiency and efficacy of management programs and help to ensure continued public and government support for ongoing mitigation of the feral pig problem. Proc. 26 th Vertebr. Pest Conf. (R. M. Timm and J. M. O'Brien, Eds.) Published at Univ. of Calif., Davis. 2014. Pp. 281-286.
... Grazing and browsing by feral goats has significant impacts on native vegetation in the rangelands (Harrington 1976Harrington , 1986 Greene et al. 1998). This is because of the relatively high densities of feral goats in the environment (West and Saunders 2007) and because feral goats feed differently to native herbivores such as kangaroos, which have evolved with native plant species over millions of years, both in terms of the species they consume and the way they feed upon them (Parkes et al. 1996). This can lead to changes in species composition as more palatable species are eaten and removed, as well as changes in vegetation structure (Wilson et al. 1976; Harrington 1976 Harrington , 1986 Henzell 1992; Landsberg and Stol 1996). ...
... Feral goats are widespread across New South Wales, but their distribution and ecology changes from east to west (West and Saunders 2007). In eastern New South Wales where rainfall is higher, they live in isolated high density populations with small home ranges and can acquire their water requirements from forage (Fleming 2004; West and Saunders 2007). In contrast, in the arid and semiarid rangelands of western New South Wales their populations are contiguous (West and Saunders 2007) although lower in density with larger home ranges (Freudenberger and Barber 1999) and they must drink regularly to meet their water requirements (Sarawaswat and Sengar 2000). ...
... Live trapping has been one of the most common forms of feral pig control used by conservation organisations, government bodies, and private landholders (Reddiex et al. 2006, West andSaunders 2007). Unlike the U.S., neck snares are not permissible in Australia. ...
... This high-level planning and prioritisation has facilitated research that has described the distribution and relative abundance of feral pigs at national and regional scales (e.g., West and Saunders 2007), identified and mapped high-value sites where feral pigs co-occur with susceptible species or ecosystems at national and statewide scales (Anonymous 2010), improved our understanding of some of their impacts (e.g., Mitchell 2010), broadened the range of control methods available to reduce pig impacts and numbers (e.g., Lapidge et al. 2012), and elucidated the roles of different social and economic factors that can influence the efficacy of feral pig management (e.g., Gentle and Pople 2013, Koichi et al. 2013). Importantly, it has also provided targeted funding for on-ground management and control programs to reduce specific, high-priority threats, such as aerial shooting programs to reduce predation on marine turtle nests. ...
