|Scientific Name:||Macrotis lagotis|
|Species Authority:||(Reid, 1837)|
Several subspecies have been described:
M. l. lagotis (Reid, 1837). South-west of Western Australia (extinct)
M. l. cambrica Troughton, 1932. Eastern New South Wales (extinct)
M. l. grandis Troughton, 1932. South-eastern South Australia (extinct)
M. l. interjecta Troughton, 1932. Nullarbor Plain, Western Australia (extinct)
M. l. nigripes (Jones, 1923). South Australia (extinct)
M. l. sagitta (Thomas, 1905). Central Australia.
However, genetic research suggests that currently-extant subpopulations (including the isolated subpopulation in south-western Queensland) show very little genetic variation (Moritz et al. 1997) and the subspecies are unlikely to be valid. As the former distribution was more or less continuous, extinct subspecies are equally unlikely to be valid. No subspecies are recognised in the 2012 Action Plan.
|Red List Category & Criteria:||Vulnerable C1 ver 3.1|
|Assessor(s):||Burbidge, A.A. & Woinarski, J.|
|Reviewer(s):||Johnson, C.N. & Hawkins, C.|
|Contributor(s):||Johnson, K., Legge, S., Copley, P., Gordon, G., Hayward, M., McGilvray, A., McRae, P., Morris, K., Paltridge, R. & Van Weenen, J.|
The Bilby is evaluated as Vulnerable because, although it still has a large extent of occurrence (EOO), it is patchily distributed and has a small area of occupancy (AOO); the population size is estimated to be fewer than 10,000 mature individuals, and it suffers from an ongoing decline estimated to exceed 10% over the last 3 generations (12 years) that is likely to continue. Five translocations, one to an island and four to mainland islands, while providing valuable ‘insurance’ against extinction, may not yet fully offset the continuing decline in the wild. Additionally, ‘A taxon may be moved from a category of higher threat to a category of lower threat if none of the criteria of the higher category has been met for five years or more’ (IUCN 2001) and even if the growth in numbers in translocated subpopulations offsets the decline in the wild, this has not been the case for >5 years for the Bilby
|Previously published Red List assessments:|
The Bilby formerly occurred over 70% of arid and semi-arid mainland Australia south of latitude 18°S. It appears to have become extinct in New South Wales and southern South Australia around the 1940s (Copley et al. 2003) or more likely, from Aboriginal knowledge, at least the 1950s (P. Copley pers. comm.). It disappeared from the Flinders Ranges in the 1920s (Tunbridge 1991) and from northern South Australia in the 1930s. The species declined dramatically in south-western Australia in the 1920s and 1930s, although it may have persisted until the 1970s or even the 1980s (Abbott 2001). It occurs patchily on the Dampier Peninsula, Western Australia.
The range of the Bilby has declined northwards and the decline is continuing. Wild subpopulations are now restricted predominantly to the Tanami Desert (Northern Territory), the Gibson, Little Sandy and Great Sandy Deserts (Western Australia), parts of the Pilbara (Western Australia) and an outlying series of disjunct subpopulations associated with both sides of the Diamantina River channels within the stony and clay chenopod plains approximately between Boulia and Birdsville (south-western Queensland) (Johnson 2008, Gibson et al. 1990). Historically, the area occupied by Bilbies in Queensland has declined by >95% (McRae 2004) and there has been a recent further significant decline.
It was successfully introduced to Thistle Island (39 km2), South Australia in 1998. It has been reintroduced to the Arid Recovery Reserve mainland island near Roxby Downs in 2000, 2003 and 2005 (South Australia; 123 km2 of which 60 km2 are free of all Rabbits, Red Foxes and Cats: Moseby et al. 2011) and to mainland islands at Scotia Sanctuary in 2004 (c. 80 km2) in western New South Wales and Yookamurra Sanctuary in 2007 (c. 11 km2) in South Australia (M. Hayward pers. comm.). It has been reintroduced to François Peron National Park, Shark Bay in 1997 and to Lorna Glen, a former pastoral station in the eastern Murchison of Western Australia where Red Foxes and feral Cats are controlled, with 128 captive-bred Bilbies being released between 2007 and 2009 (K. Morris pers. comm.). Bilbies will be reintroduced to Mt Gibson Sanctuary in Western Australia once the fence around the mainland island (40-60 km2) is complete (S. Legge pers. comm.).
The southern edge of Bilby distribution in the Northern Territory has contracted north by >100 km per decade over the past twenty years (Paltridge and Eldridge 2009). Bilbies are now restricted to areas of the Tanami Desert where foxes are absent or at very low densities. In contrast, 2012 surveys of the southern edge of the range of the Bilby on the Ngaanyatjarra Lands in Western Australia revealed no change to the southern extent of Bilby distribution in eastern Western Australia over the past decade (R. Paltridge pers. comm.).
Native:Australia (New South Wales - Regionally Extinct, Northern Territory, Queensland, South Australia, Victoria, Western Australia)
|Range Map:||Click here to open the map viewer and explore range.|
Available estimates from Friend et al. (2008) and subsequent information, based on a variety of counts, density estimates and other methodologies, are:Natural subpopulations
Western Australia: 5000-10 000
Northern Territory: <1000
Queensland: 200-500 (however, there has been a subsequent recent significant decline, largely due to Cat predation)Reintroduced subpopulations
Thistle Island (South Australia): c. 500 individuals
Lorna Glen (Western Australia): a 2012 survey estimated between 128 and 339 bilbies (N. Burrows pers. comm.).
Mainland island subpopulations:
Peron Peninsula, François Peron National Park (Western Australia): 200
Venus Bay (South Australia): 100
Arid Recovery (Roxby Downs, South Australia): 500
Yookamurra (South Australia): 200 (2012)
Scotia (New South Wales): 1900 (2012)Currawinya National Park (Queensland): estimated at 150, recently declined as a result of Cat invasion.
Across natural, introduced and mainland island subpopulations, these estimates tally to c. 9000-15 000 individuals; the number of mature individuals would be fewer. We consider the figure for Western Australia to be high; and assume the number of mature individuals to be <10 000. The limited available information suggests a current decline in at least some natural subpopulations (and at least one mainland island population), with this decline not yet outweighed by increasing size and number of translocated subpopulations.
Captive colonies are managed as two separate units. Queensland colonies are held by Currumbin Wildlife Sanctuary, David Fleays Wildlife Park, Dreamworld, Ipswich Nature Centre, Wildlife Sydney and Taronga Zoo; Northern Territory colonies are managed via a Conservation Program involving Adelaide Zoo, Alice Springs Desert Park, Australia Walkabout Wildlife Park, Cleland Wildlife Park, Halls Gap Zoo Healesville Sanctuary, Melbourne Zoo, Monarto Zoological Park, and Perth Zoo (Ford and Hogg 2012).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
Bilbies are a solitary species, sheltering in burrows, which may be up to 3 m deep and often descend in a spiral. Burrows are usually isolated, but may be complex and there may be many within a relatively small area; an individual Bilby may dig more than 12 burrows within its home range. Bilbies are nocturnal and burrows are occupied during daylight and intermittently during the night. An omnivore, the Bilby eats a variety of plant and animal materials, including grass and sedge seeds, bulbs particularly from Bush Onion Cyperus bulbosus, and invertebrates, especially termites, but also ants, spiders, beetles and insect larvae (Southgate 1990b; Navinth et al. 2009). Most food is obtained by digging. Mature males range more widely than females and have been recorded occupying burrows over 5 km apart on consecutive days (Southgate and Possingham 1995; McRae 2004). Estimates of short-term home range sizes in the Northern Territory varied from 1.1 to 3 km2 (Southgate and Paltridge 1998). Mean home range sizes recorded from wild populations in Queensland are 51 ha for males and 20 ha for females. Burrow ranges are considerably smaller at 15.3 ha for males and 3 ha for females (McRae 2004).
Remaining subpopulations occupy three major vegetation types: open tussock grassland on uplands and hills, mulga woodland/shrubland growing on ridges and rises, and hummock grassland in plains and alluvial areas. Bilbies will move to new home ranges once food becomes scarce. At Watarrka National Park, one group moved 10.5 km from a release site during a three-year period (Southgate and Possingham 1995).
|Generation Length (years):||4|
|Movement patterns:||Not a Migrant|
|Major Threat(s):||The major threat to the Bilby is predation by introduced red foxes and feral cats, exacerbated by changed fire regimes. Predation by dingoes, and habitat degradation by livestock are lesser threats.|
A 2006 recovery plan (Pavey 2006) included the following actions
· Control predators at key Bilby populations
· Continue husbandry and coordinated management of captive populations
· Continue to reintroduce the species to predator-free or predator-controlled sites across its former range
· Refine monitoring methodology
· Monitor trends in occurrence and abundance of the greater Bilby across its range including at reintroduction sites
· Measure impact of threatening processes on Bilby populations at reintroduction sites.
An updated recovery plan is in preparation. Implementation is ongoing. The national Bilby recovery team meets irregularly (every 3-4 years) as part of national arid zone threatened fauna forums. Predator control is limited to semi-captive, fenced subpopulations, except for small-scale predator control conducted by the Central Land Council utilizing fox-specific bait stations at a key Bilby subpopulation in the Tanami Desert (R. Paltridge pers. comm.). Reintroduction was attempted at Dryandra (WA), where fox control is in place; however it was not successful due to predation by remaining and immigrating foxes as well as feral Cats. An introduction to the 39 km2 Thistle Island (South Australia) has been successful, as has a reintroduction to the 123 km2 Arid Recovery Reserve mainland island, Roxby Downs (South Australia which is free of all Rabbits, Red Foxes and Cats (Moseby et al. 2011). Aerial and ground surveys have been conducted in south-west Queensland and limited surveys have been carried out in the Tanami Desert, Northern Territory. A re-introduction to Venus Bay peninsula (South Australia) appears to have been successful initially, and then failed due to the presence of feral Cats within the fenced area. The presence and occurrence of Bilby is being monitored in Western Australia’s desert rangelands through a partnership with Rangelands NRM, Department of Environment and Conservation, Kanyirninpa Jukurrpa and Central Desert Native Title Services. The track-based monitoring methodology has been applied (Southgate and Moseby 2008) across a large area, including Birriliburu, Martu, Ngurrupa and Spinifex native title determinations, and the Pilki and Yilka native title claim areas. Bilby sign has been detected in the Martu and Birriliburu determinations, and on-ground activities to protect these populations are being implemented by the traditional owners.
In Queensland, Bilby subpopulations are managed via control of introduced predators. Some indigenous ranger groups in the Northern Territory and Western Australia are carrying out fire and predator management. In the desert rangelands area of Western Australia, traditional owners are implementing on-ground activities in areas where Bilbies have been detected through the track-based monitoring program, the key activity being implemented being cool-season patch burning to create a diversity of food resources and habitat, and shelter from predators. Traditional hunting of predators is also encouraged in the desert rangelands, particularly close to Aboriginal communities on country, though the feasibility of maintaining low densities of predators in more remote areas through traditional hunting is very limited. In the Tanami Desert, Northern Territory, the Central Land Council is developing a discriminatory baiting program at one of the most important Bilby sites. Studies of predator diets in this area have revealed a high proportion of Cat remains in Dingo scats. In an attempt to control the fox population without affecting the resident Dingoes, fox-specific bait stations are being trialled in habitats frequented by Dingoes. Expert tracking skills also assist strategically placement of fox baits on the ground along regularly used fox trails and broad-scale baiting is being conducted in surrounding habitats where Dingoes and Bilbies only occasionally occur, to create a buffer zone of low fox density (R. Paltridge pers. comm.). In the Kiwirrkurra-Lake Mackay region of Western Australia, Bilbies are persisting at sites where Pintubi continue to conduct regular Cat hunting and frequent patch burning (R. Paltridge pers. comm.).
|Citation:||Burbidge, A.A. & Woinarski, J. 2016. Macrotis lagotis. The IUCN Red List of Threatened Species 2016: e.T12650A21967189.Downloaded on 21 August 2017.|
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