Survey guidelines for Australia’s threatened non-flying mammals

Numbat

Myrmecobius fasciatus

States and territories: Western Australia.

Regions: South-western Western Australia reintroduced to some areas in NSW and South Australia.

Habitat: Remnant patches of wandoo and jarrah forests (Friend & Thomas 2003).

Habit: Ground-dwelling.

Avg. body weight: 471.5 g (females heavier than males) (Friend 1995).

Activity pattern: Diurnal.

Diet: Termites (Friend 1995).

Breeding: Breed once a year between February and April, with two to four offspring per litter (Friend 1995).

Description

The numbat is a small, brightly coloured dasyurid that is the only marsupial adapted to a diet of termites (Friend 1995). The species had a former distribution across much of southern Australia, from south-west Western Australia to western NSW. Its range is now restricted to a few isolated populations around Dryandra and Perup reserves in Western Australia (Friend 1995), but the numbat has been reintroduced to a number of other sites in the vicinity of these populations with mixed success (Friend & Thomas 2003). In south-western Western Australia, the species’ known preferred habitat is mostly wandoo, powderbark wandoo and jarrah forests (Friend & Thomas 2003).

Numbats are diurnal and shelter in hollow logs and burrows, including those dug by other species (Bester et al. 2006; Cooper & Withers 2005). Cooper and Withers (2005) found that numbats may prefer burrows to hollow logs as shelters because they are better insulated than hollow logs and may offer better shelter from climatic extremes. However, Bester and colleagues (2006) suggested that their observations of higher burrow use than hollow log use reflects the availability rather than preference for these refuges. Numbats forage for termites by digging small holes in the ground (Friend 1995). They are mostly solitary, and their activity patterns appear to follow the availability of termites in the upper soil layers (Friend 1995), being most active in the early morning and late afternoon (Cooper & Withers 2004).

Numbats are a conspicuous species and their decline throughout their range has been well documented, particularly in the settled areas of the wheatbelt in Western Australia (Friend 1990; Peacock 2006). The primary reasons for the decline of the numbat include the introduction of feral predators, in particular foxes and cats (Friend & Thomas 2003). The control of introduced predators has been the key to the maintenance of extant populations of numbats and for the establishment of reintroduced populations (Friend 1990). Altered fire regimes and the clearing of bush for agriculture are also considered to play a role in the species’ decline (Friend & Thomas 2003).

Survey methods

Consultation with the Science Division within the Western Australian DEC is advisable prior to undertaking surveys. Numbats appear capable of dispersing away from sites where they have been released, especially in areas not surrounded by farmland (Friend & Thomas 2003) and this should be considered when surveying near known numbat populations. The following survey techniques are recommended to detect the presence of the numbat in areas up to 5 hectares in size:

• 
  daytime searches for potentially suitable habitat resources, particularly in mature wandoo woodland in Western Australia, and areas with hollow logs and termite mounds (description of the survey technique and recommended effort is outlined in Section 3.1)
  
• 
  daytime searches for signs of activity, including tracks, scats 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, modified such that soil is raked smooth around potential foraging or shelter sites to facilitate the detection of tracks
  
• 
  daytime searches for active fauna conducted either on foot or from a vehicle in the manner described and according to the effort recommended in Section 3.3.1
  
• 
  possibly conducting observations at potential shelter sites, such as a burrow or a hollow log (description of the survey technique and recommended effort outlined in Section 3.3.4)
  
• 
  collection of predator scats, owl casts or remains, targeting predatory bird/reptile/mammal nests/dens (description of the survey technique and recommended effort is outlined in Section 3.2).
  

Should confirmation of the species’ presence be required after detection of signs, then observations conducted at potentially active den sites at dawn or dusk, when the numbat leaves and returns to its den may produce a direct observation.

Similar species in range

There are no species that are similar in appearance to the numbat.

References

Bester, A., Rusten, K. and Moseby, K. 2006. Returning numbats to the outback- a trial release of numbats into the arid recovery reserve. Australian Mammal Society Conference Proceedings, Melbourne, Victoria. p. 65

Cooper, C.E. and Withers P.C. 2004. Influence of season and weather on activity patterns of the numbat (Myrmecobius fasciatus) in captivity. Australian Journal of Zoology 52: 475-485
Cooper, C.E. and Withers P.C. 2005. Physiological significance of the microclimate in night refuges of the numbat Myrmecobius fasciatus. Australian Mammalogy 27: 169-174
Friend, J.A. 1990. The numbat Myrmecobius fasciatus (Myrmecobiidae): history of decline and potential for recovery. Proceedings of the Ecological Society of Australia 16: 369-377
Friend, J.A. 1995. Numbat, Myrmecobius fasciatus. In ‘The Mammals of Australia’. (Ed. R. Strahan) pp. 160-162 (Reed Books: Sydney).
Friend, J.A. 2008. Numbat, Myrmecobius fasciatus. In ‘The Mammals of Australia’. (Eds. S. Van Dyck and R. Strahan) pp. 163-165 (Reed New Holland: Sydney).
Friend, J.A. and Thomas, N.D. 2003. Conservation of the Numbat (Myrmecobius fasciatus). In Predators without Pouches. pp. 446-457. CSIRO Publications.
Peacock, D.E. 2006. Historical accounts of the numbat Myrmecobius fasciatus from south-west Western Australia. Australian Mammalogy 28: 97-100
Vieira, E.M., Finlayson, G.R. and Dickman, C.R. 2007. Habitat use and density of numbats (Myrmecobius fasciatus) reintroduced in an area of mallee vegetation, New South Wales. Australian Mammalogy 29: 17-24.