Survey guidelines for Australia’s threatened non-flying mammals

Brush-tailed rabbit rat

Conilurus penicillatus

States and territories: Western Australia, Northern Territory and Queensland.

Regions: Formerly monsoonal near-coastal northern Australia, from the northern Kimberleys, principally in the Mitchell Plateau area, east to around Burketown in the Gulf country of Queensland. Also some adjacent offshore islands with relatively high rainfall, including the Tiwi Islands, Inglis Island, Groote Eylandt, the Sir Edward Pellew Group off the Northern Territory and Bentinck Island in the Wellesley Group in the Gulf of Carpentaria off Queensland. Now it is highly localised and patchily distributed with only two sites known on the mainland of the Northern Territory: the Cobourg Peninsula and the Mardugal area of Kakadu National Park. The species also occurs in small areas of southern New Guinea.

Habitat: The primary habitat is mixed eucalypt tall open forest and woodland, or on the Cobourg Peninsula it occurs in coastal grasslands with scattered tall ironwood Casuarina equisetifolia, stunted eucalypts on stony slopes and on beaches (Woinarski 2007). Important factors in the landscape (excluding the Cobourg Peninsula) include open forest with taller trees, less frequent (or less intense) fires, sparse grass cover, distance from watercourses or moist areas, and the presence of tree hollows (Firth et al. 2005, 2006a). The brush-tailed rabbit rat shelters primarily in tree hollows and fallen logs; occasionally in the crowns of Pandanus and sand-palms (Firth et al. 2006b).

Habit: Ground and tree-dwelling.

Avg. body weight: 163 g (males) and 144 g (females) (Kemper & Firth 2008).

Activity pattern: Nocturnal, although often active at dusk.

Diet: Predominantly seeds (especially of grasses), with some fruits, leaves, grass and invertebrates also consumed (Firth et al. 2005).

Breeding: Breeds between March and October, during which time several litters comprising one to four (usually three) young are born (Kemper & Firth 2008).

Description

The brush-tailed rabbit rat is the only extant member of its genus, with its sole congener the white-footed rabbit rat C. albipes becoming extinct by the late 1860s (Dixon 2008). It is a large, partly arboreal rat that has a long brush-tipped tail and long ears. Although formerly reported as common (for example, Dahl 1897), it has declined across much of its range. Estimations suggest its distribution and population size has declined by over 50 per cent since European settlement in the Northern Territory (Woinarski 2000). Reasons for the decline of this species are unclear, but are possibly associated with a combination of factors, including disease, predation by feral cats and broad scale habitat changes through more frequent and extensive fires, weeds and changes in food availability as a result of grazing pressure from introduced grazers and domestic livestock (Firth et al. 2005, 2006a).

Survey methods

On the basis of previous surveys, the following survey techniques are recommended to detect the presence of the brush-tailed rabbit rat in areas up to 5 hectares in size:

• 
  daytime searches outside the Cobourg Peninsula for potentially suitable habitat resources such as open forest with taller trees, less frequent (or less intense) fires, sparse grass cover, and distance from watercourses or moist areas (description of the survey technique and recommended effort is provided in Section 3.1)
  
• 
  daytime searches on the Cobourg Peninsula for potentially suitable habitat resources such as coastal grasslands with scattered tall ironwood, stunted eucalypts on stony slopes and on beaches (description of the survey technique and recommended effort is provided in Section 3.1)
  
• 
  trapping surveys using Elliott traps (conducted according to the technique description and recommended effort provided in Section 3.3.9) and cage traps (according to the technique description and recommended effort provided in Section 3.3.10) are the best techniques for targeted surveys of this species
  
• 
  spotlight surveys conducted according to the technique description and recommended effort provided in Section 3.3.3.
  

Similar species in range

The brush-tailed rabbit rat occurs sympatrically with two other large rat species: the black-footed tree rat Mesembriomys gouldii and the golden-backed tree rat M. macrurus. It is distinguished from the black-footed tree rat by its smaller size (less than 600 grams in weight), short muzzle, and lack of black feet and ears. The golden-backed tree rat has an entirely whiteish coloured tail; the tail of the brush-tailed rabbit rat is black on the basal half with a dense tuft of either black or white fur on the end half to third. The golden-backed tree rat also has a distinct golden dorsal band.

References

Bradley, A.J., Foster, W.K. and Taggart, D.A. 2008. Red-tailed Phascogale Phascogale calura. In ‘The Mammals of Australia’ (Ed. S. Van Dyck and R. Strahan) pp. 101-102 (Reed New Holland: Sydney).

Dahl, K. 1897. Biological notes on the north-Australian mammalia. The Zoologist 671: 189-216.
Dixon, J.M. 2008. White-footed rabbit rat Conilurus albipes Pp. 578-579. In Van Dyck, S. and Strahan, R. (Eds.) The Mammals of Australia. Third Edition. Reed New Holland, Sydney.
Firth, R.S.C., Jefferys, E., Woinarski, J.C.Z. and Noske, R.A. 2005. The diet of the Brush-tailed rabbit rat Conilurus penicillatus from the monsoonal tropics of the Northern Territory, Australia. Wildlife Research 32: 517-524.
Firth, R.S.C., Woinarski, J.C.Z., Brennan, K.G. and Hempel, C. 2006a. Environmental relationships of the Brush-tailed rabbit rat Conilurus penicillatus, and other small mammals on the Tiwi Islands, northern Australia. Journal of Biogeography 33: 1820-1837.
Firth, R.S.C., Woinarski, J.C.Z. and Noske, R.A. 2006b. Home range and den characteristics of the Brush-tailed rabbit rat Conilurus penicillatus from the monsoonal tropics of the Northern Territory, Australia. Wildlife Research 33: 397-408.
Kemper, C.M. and Firth, R.S.C. 2008. Brush-tailed rabbit rat Conilurus penicillatus. ‘The Mammals of Australia’ (Ed. S. Van Dyck and R. Strahan) pp. 579-581 (Reed New Holland: Sydney).
Woinarski, J.C.Z 2000. The conservation status of rodents in the monsoonal tropics of the Northern Territory. Wildlife Research 27: 21-35.
Woinarski, J. 2007. Threatened Species Information Sheet: Brush-tailed rabbit rat, Conilurus penicillatus. Department of Natural Resources, Environment and the Arts, Darwin.
Woinarski, J.C.Z., Palmer, C., Fisher, A., Southgate, R., Masters, P. and Brenan, K. 1999. Distributional patterning of mammals on the Wessel and English Company Islands, Arnhem Land, Northern Territory, Australia. Australian Journal of Zoology 47: 87-111.