Survey guidelines for Australia’s threatened non-flying mammals

Boodie, burrowing bettong (Barrow and Boodie Island)

Bettongia lesueur unnamed subsp.

States and territories: Western Australia.

Regions: Boodie and Barrow Islands, off the Pilbara coast.

Habitat: On Barrow Island, burrows are almost always associated with limestone cap-rock on slopes and the top of ridges; some are in the floor of caves (Burbidge & Short 2008).

Habit: Ground-dwelling (burrows).

Avg. body weight: 680 g (Burbidge 1995).

Activity pattern: Nocturnal.

Diet: Herbivore: tubers, seeds, nuts and plants.

Breeding: Undescribed for Boodie and Barrow Islands.

Description

The burrowing bettong’s range previously covered much of arid western and central Australia, but it is now restricted to Dorre and Bernier Islands in Shark Bay and Boodie and Barrow Islands off the Western Australian coast (Short & Turner 1993). The Shark Bay subspecies of burrowing bettongs from Dorre Island were re-introduced to a fenced, predator-free mainland site, Heirisson Prong in Shark Bay (Sander et al. 1997). Pizzuto and colleagues (2007) found that a reintroduced population of burrowing bettong in western NSW selected microhabitats with up to 25 per cent canopy cover, one to two centimetres deep litter and open structure at ground level for nocturnal foraging and other activities.

The burrowing bettong is nocturnal and gregarious (Burbidge 1995). The only burrowing macropod to regularly shelter underground, they dig burrows that range from a simple structure with one or two entrances and short, shallow tunnels, to complex, interconnected warrens (Burbidge 1995). On Barrow Island, warrens with up to 90 entrances have been recorded (Sander et al. 1997). Local soil type constrains burrow complexity, and sandy soils usually support only simple burrows (Ride et al. 1962). The burrowing activities of this species created and maintained surface soil heterogeneity and influenced the composition of the plant communities in arid regions, and despite local extinction of this species across much of Australia, relict warrens still exert an impact on floral diversity and productivity (Noble et al. 2007).

Survey methods

A Wayne (Western Australian DEC, 2009) noted the importance of minimising disturbance to bettongs during trapping programs because of their tendency to reject pouch young when stressed. Passive means of detecting this species, like baited camera traps, are preferable in situations where trapping is not necessary. If trapping is necessary animal handling should be undertaken with caution.

The following survey techniques are recommended to detect the presence of the burrowing bettong in areas up to 5 hectares in size:

• 
  daytime searches for potentially suitable habitat resources, which includes a wide range of habitat types within the islands of the species known range (description of the survey technique and recommended effort is outlined in Section 3.1)
  
• 
  daytime searches for signs of activity, including burrows, diggings, tracks and scats (description of the survey technique and recommended effort is outlined in Section 3.2).
  
• 
  collection of predator scats, owl casts or remains, targeting predatory bird and mammal nests and dens (description of the survey technique and recommended effort is outlined in Section 3.2)
  
• 
  soil plot surveys conducted according to the description of the technique and the recommended effort provided in Section 3.3.2.
  

If confirmation of the species is required from the presence of signs, then one or more of the following survey techniques should be employed:

• 
  observations conducted at dusk/early night at burrow entrances according to the description of the technique and the recommended effort provided in Section 3.3.4
  
• 
  spotlight surveys conducted according to the description of the technique and the recommended effort provided in Section 3.3.3
  
• 
  cage trapping surveys conducted according to the description of the technique and the recommended effort outlined in Section 3.3.10, using a mixture of peanut butter, rolled oats, sardines or bacon for bait. A fence trapping system, similar to that devised for the bilby Macrotis lagotis by Southgate and colleagues (1995) and Gibson and Hume (2000) may also be appropriate (see the species profile for the bilby) for capturing the burrowing bettong as individuals emerge from their burrows
  
• 
  camera traps baited with universal bait and added almond, walnut or truffle oil (see potoroo profiles for further information) are likely to prove useful for positively identifying and minimising impact on animals and are also cost-effective (description of the survey technique and recommended effort is outlined in section 3.3.6).
  

The burrowing bettong is not distinguishable from hair samples (see Table 2, Section 3.3.6). Should this situation change, then hair sampling may provide an appropriate alternative detection technique, however this method should be used only as part of an integrative approach utilising other methods like baited camera traps.

The survey method recommended has been designed for surveys of areas within the burrowing bettong's known range. Should surveys be required on the mainland, then further expert advice should be sought from the relevant government authorities. Any signs of the burrowing bettong on the mainland should be reported immediately to the Western Australian DEC or other relevant government authorities.

Similar species in range

There are no other bettongs on the islands; however, a number of other macropodoidea species occur on Barrow Island and their tracks may be indistinguishable from those made by the burrowing bettong, particularly if made by smaller-sized juveniles. The wallaby and kangaroo species include the spectacled hare wallaby Lagorchestes conspicillatus conspicillatus, the black-flanked rock wallaby Petrogale lateralis lateralis and the Barrow Island euro Macropus robustus isabellensis, all of which are listed on the EPBC Act. In addition, the golden bandicoot Isoodon auratus also occurs on Barrow Island, but bandicoot tracks are distinguished from those of the burrowing bettong by the presence of three clawed toes on the forepaws rather than five. Baited camera traps will aid in the positive identification of species in this circumstance.

References

Burbidge, A.A. and Short, J.C. 2008. burrowing bettong Bettongia lesueur. In ‘The Mammals of Australia’ (Eds. S. Van Dyck and R. Strahan). pp. 288-290. (Reed New Holland, Sydney).

Gibson, L.A. and Hume, I.D. 2000. Seasonal field energetics and water influx rates of the greater bilby (Macrotis lagotis). Australian Journal of Zoology 48: 225-239.
Finlayson, G.R., Vieira, E.M., Priddel, D., Wheeler, R., Bentley J. and Dickman, C.R. 2008. Multi-scale patterns of habitat use by re-introduced mammals: a case study using medium-sized marsupials. Biological Conservation 141(1): 320-331.
Noble, J.C., Müller, W.J., Detling, J.K. and Pfitzner, G.H. 2007.Landscape ecology of the burrowing bettong: warren distribution and patch dynamics in semiarid eastern Australia. Austral Ecology 32(3): 326-337
Pizzuto T.A., Finlayson, G.R., Crowther, M.S. and Dickman, C.R. 2007. Microhabitat use by brush-tailed (Bettongia penicillata) and burrowing bettongs (B. lesueur) in semiarid NSW: implications for reintroduction programs. Wildlife Research 34: 271-279.
Ride, W.D.L., Mees, G.F., Douglas, A.M., Royce, R.D. and Tyndale-Biscoe, C.H. 1962. The results of an expedition to Bernier and Dorre Islands, Shark Bay, Western Australia. Fisheries Department, Western Australia.
Sander, U., Short, J. and Turner, B. 1997. Social organisation and warren use of the burrowing bettongs, Bettongia lesueur (Marsupialia: Potoroidae). Wildlife Research 24: 143-157.
Short, J. and Turner, B. 1993. The distribution and abundance of the burrowing bettong (Marsupialia: Macropodoidea). Wildlife Research 20: 525-534.
Short, J., Richards, J.D. and Turner, B. 1998. Ecology of the western barred bandicoot (Perameles bougainville) (Marsupialia: Peramelidae) on Dorre and Bernier Islands, Western Australia. Wildlife Research 25:567-586.
Short, J. and Turner, B. 1999. Ecology of burrowing bettongs, Bettongia lesueur (Marsupialia: Potoroidae), on Dorre and Bernier Islands, Western Australia. Wildlife Research 26: 651-669.
Southgate, R.I., McRae, P. and Atherton, R.G. 1995. Trapping techniques and pen design for the greater bilby Macrotis lagotis. Australian Mammalogy 18: 101-104.