Unlike many of Australia’s other native species, the Common Brushtail Possum Trichosurus vulpecula has flourished in the face of urban development. This highly adaptable animal has successfully established itself in many urban areas. However, developed areas often suffer from a shortage of mature trees bearing hollows - this makes for a housing crisis for the average Brushtail Possum.
Brushtail Possums eat a variety of leaves (particularly eucalyptus), flowers, fruits, buds and bark off both native and exotic trees and shrubs. They may also eat fungi, insects, bird’s eggs, and baby birds. On a gum leaf diet it is thought that the toxins in eucalypt foliage make it necessary for them to top up with pasture plants eg: clover and lawn weeds. In cities they will often by found feeding on vegetable and fruit scraps from domestic compost heaps, and have been known to scrounge any left-over pet food left unattended.
In contrast, the Common Ringtail Possum Pseudocherius peregrinus seldom shelters in buildings, preferring to construct its dray (nest) of twigs and leaves in dense vegetation a few meters above the ground. This smaller possum feeds on leaves and buds on a variety of native and ornamental plants including roses. The Ringtail Possum usually gains access to its food via other trees and shrubs, or overhead wires, rather than venturing downwards to the ground.
In many States, live-trapping and relocation of possums has in the past been widely used to relieve human-possum conflict, on the basis that it is more humane to move nuisance animals to a location where they can settle and no longer come into conflict with humans. It was generally believed that possums moved to a forest habitat would survive and readily become adapted to their new environment. Unfortunately, possums disposed of by well-meaning residents in nearby parks or bushland die within a short period of time.
A study undertaken by Latrobe University on hand-reared Common Ringtail Possums released into a forest near Healesville, had a mere 10% survival rate within two weeks. Another by the University of New South Wales on Ringtail Possums released into Ku-ring-gai Chase National Park, NSW reported on the fate of 82 relocated animals marked with radio-transmitters - 98% of these animals were soon killed by predators, with a average survival time of only 75 days.
A Deakin University study on 64 Common Brushtail Possums released on a site in Silvan showed that 88% of the released possums died within the first week. Of the 12 Brushtail Possums fitted with radio collars only two survived for more than two months. The reasons attributed to the alarming mortality rate were predation by foxes, stress associated with relocation to a foreign environment, and road kill. In Victorian alone, some 4,000-5,000 possums are taken to the RSPCA each year by licensed possum controllers, with many more being trapped and relocated illegally by the public.
It is interesting to note that immediately following release, more than half the Brushtail Possums that tried to climb nearby trees either slipped or fell. These possums also spent considerably more time traveling and where frequently found in log piles on the ground or sitting in tree forks with no cover during daylight. As a result of previous human interaction, the relocated possums were also less likely to react at the approach of a predator. This was not observed in resident animals that rapidly retreated out of sight or climbed a tree to a safe distance.
Like all native Australia animals, possums are protected. In most states, a licensed wildlife controller in purpose-built traps can only trap possums. They must then be released within the immediate area. If this is not desirable, they must by law be taken to a registered veterinarian to be killed humanely - at the householders’ expense.
Ideally, a possum trapped in your roof should be released into a nest box in your garden ie: its own territory. Nest boxes can be purchased, or you can build your own to plans available from government wildlife agencies. Merely removing a possum from your roof will not solve the problem - as another possum will occupy the vacated territory within a short time. By pruning branches that lead to your roof, fitting collars around trees, possum proofing transmission cables, and building a floppy fence on top of an existing paling fence, will all discourage entry, and prevent future access into your roof by possums.
Despite its wide distribution, broad dietary tastes, relatively high reproduction output and its ability to co-exist with humans, not all is well with the Brushtail Possum. Past disappearances from central Australia and present dramatic declines in northern Queensland, show that the Brushtail Possums range is decreasing, and in much of the arid interior they have disappeared altogether.
Relocating possums is both inhumane, and prohibited by law. Perhaps the past trend of relocating possums should be seen as an ill-informed one, and the option of cohabiting with our unique wildlife a far more desirable solution. Possums are part of suburban living, and here to stay.
© Donna Racheal 2007