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Common brushtail possum (Trichosurus vulpecula)
The common brushtail possum Trichosurus vulpecula, Noongar name Koomal, was once very widespread, occurring throughout Australia, including Tasmania and inland deserts. Nowadays it has almost disappeared from the more arid and semi-arid parts of Australia, and is largely restricted to higher rainfall areas. As is the case with many medium-sized Australian mammals, the decline is mostly due to predation by Red Foxes and feral Cats, although land clearing for agriculture has also impacted the species. In Western Australia, they occur on Barrow Island, which has no trees, and they spend most of their time on the ground. They were introduced to New Zealand in 1850 and later to develop a fur trade, once having a population size of 60-70 million. They remain a major pest.
In the Perth metropolitan area it occurs in remnant bushland and sometimes in private gardens. Fur colour varies in different parts of Australia, but possums from the south-west of WA typically have grey fur and often have a white tip to the tail.
Common Brushtail Possums feed on a variety of plants, leaves, fruits and flowers, sometimes also taking nestling birds. They sleep in tree hollows or similar protected nooks, including the ceilings of buildings. When they formerly occurred in western deserts in treeless areas they often sheltered in warrens dug by the boodie (or burrowing bettong Bettongia lesueur).
They can breed at any time of the year, but mostly in spring and autumn. A newborn brushtail possum is only 1.5 cm long and weighs only 2 g. As is usual for marsupials, the newborn may climb unaided, through the female's fur into the pouch and attach to a teat. The young develops and remains inside the mother's pouch for 4–5 months. Once the single joey leaves its mother’s pouch, it is carried on her back until 7-9 months old.
As is the case with all indigenous vertebrate animals in WA, they are a protected species, and people who want them removed from their roof must contact a licensed possum removalist.
At Perry Lakes they are not common but may be sighted at night with the aid of a strong torch; look for eye shine. They are more abundant in Bold Park.
Image credit: Andrew Mercer (www.baldwhiteguy.co.nz), CC BY-SA 4.0, via Wikimedia Commons
Quenda (Isoodon fusciventer)
The Quenda, or Isoodon fusciventer, occurs only in the south west of Western Australia. In the past it was thought that the bandicoot in the southwest was Isoodon obesulus, the southern brown bandicoot, but research at the Western Australian Museum showed that quenda was a separate species and Isoodon obesulus is now known to be restricted to eastern Australia. Like all indigenous vertebrate animals, quenda are legally protected.
Fast facts
- They're marsupials and have a pouch.
- Quenda is a Noongar name from the Perth area, although other First Nations’ names have been recorded.
- Adult body length is approx. 245 mm. Tail is short, approx. 100mm with dark brown fur. Weight: up to 2kg. Nose is long and pointed, ears are short and rounded. Fur is short, coarse and often dark grey-brown with rusty brown highlights. Belly is creamy white.
- Omnivorous, feeding on invertebrates including spiders and insects, plant material including bulbs and tubers, and underground fungi. Scats have been found to contain an average of 45 and up to 100 different fungi species.
- Their distinct digging patterns indicate their presence (they are different from rabbits).
- Contrary to popular opinion, they are not nocturnal. They are active day and night, particularly around dawn and dusk. and are less active during daylight in hot weather.
- Can become quite tame in urban areas.
Habitat
- Ground-dwelling indigenous mammal still found in Perth metro area, and a recent arrival in Perry Lakes Reserve and Bold Park, possibly self-introduced from a translocation to Shenton Bushland in 2019 or a translocation to Lake Claremont.
- Friends of Perry Lakes' and Town of Cambridge planting program will help quenda establish their population.
- Widespread in higher rainfall parts of south-west of WA, having disappeared from drier northern and eastern parts resulting in smaller geographic range than in the past.
- Fox baiting under Western Shield has led to larger populations and quenda moving into areas not previously occupied.
Ecological role
- Their propensity for digging when foraging enhances plant seed dispersal and germination. Soil and litter turnover reduces risks of high severity fire. About 45 foraging excavations in a day, turning over nearly 4 tonnes of soil annually, can lead to significant ecological benefits.
- Spores from the scats contain mycorrhizal fungi that can colonise plant roots, including eucalypts, helping them absorb water and nutrients.
Reproduction
- Peak breeding season is August and September but can reproduce all year round.
- Litter size: one to five with two most common.
- Young leave pouch fully furred at about 70mm in body length.
- Nests typically made of grass and leaf litter in mound-like structure within dense vegetation but can dig short burrows as heat refuge in hot weather.
Threats
- Predators include red foxes (introduced species), dogs and cats, both feral and domestic. It is important that pet dogs be kept on leash in the Perry Lakes reserve.
Image by David Spearman, 2024
References
Abbott, I. (2001). Aboriginal names for mammal species in south-west Western Australia. CALMScience 3, 433-486.
Hopkins, A.J.M., Tay, N.E., Bryant, G.L., Ruthrof, K.X., Valentine, L.E., Kobryn, H., Burgess, T. I., Richardson, B.B., Hardy, G. E.StJ and Fleming, P.A. (2021). Urban remnant size alters fungal functional groups dispersed by a digging mammal. Biodiversity and Conservation 30, 3983–4003. https://link.springer.com/article/10.1007/s10531-021-02287-4
Travouillon, K.J. and Warburton N.M. (2023). Quenda. In: Strahan’s Mammals of Australia. Fourth Edition, pp. 175-176. Reed New Holland Publishers, Wahroonga, New South Wales, Australia.
Valentine, L., Campbell, R., Moore, H., Beca, G., Bohórquez Fandiño, D., Palmer, B., Reaveley, A., Ryan, C., Hobbs, R., (2021). Translocation of quenda (Isoodon fusciventer) alters microhabitat of urban bushland reserve. NESP Threatened Species Recovery Hub, Brisbane.