Living with Brush-tailed Possums

The lively brush-tailed possum is one of Australia's most familiar marsupials, largely because they are highly adaptable to a wide range of natural and human environments. Their natural and preferred habitat is forest, where they nest in tree hollows. They will also cohabit with humans in cities and towns where they seek shelter, warmth and protection in the dark recesses of buildings. A favoured spot is between the ceiling and the roof and this can be a problem to some people. They can damage crops and gardens because they are partial to exotic plants, pasture grasses and vegetables as well as native plants.

The following notes provide practical information to satisfy the house and landowner having problems with brushtail problems, without harming the animal. Remember, brush-tailed possums are protected by law and cannot be bought, sold, taken or harmed except by a permit (please phone the Wildlife Services Branch on (03) 6165 4305).

Possums in your home

Is that noise in the ceiling a brush-tailed possum? Sometimes, the intruder turns out to be an introduced rat or mouse. Sometimes both possums and rats or mice are involved and separate action is required. The following signs might help to identify the culprit:

Possum scat, compared to the droppings of a black rat and house mouse.

Rats and mice make scratching, chewing and skittering noises. They have distinctive droppings, do not defecate where they are nesting and, unlike possums, may chew electrical wiring. Rats also collect seeds and grasses, but possums do not. Possums make loud heavy, thumping sounds when walking, and distinctive guttural growls, screeches, hisses and coughs when disturbed. You can find out for sure by looking inside the ceiling with a flashlight during the day or observing your house just on dark when the possum emerges.

Possum proofing

The brush-tailed possum can be the focus of complaints from urban residents for a variety of reasons. Some solutions for dealing with these issues are listed below:

1. Possums in the roof

Find out where the possum is getting in and out. More than one place may be involved. You will need to watch and listen for the animal's movements. Look for holes under eaves; loose tiles or roofing iron; or access from underneath a house up through wall cavities to the roof. Possums can squeeze through a nine-centimetre gap!
Make the necessary temporary repairs (prepare something during the day) to prevent re-entry after the possum has gone out to feed at night (they usually leave their shelter about an hour after sunset). Permanent repairs can be made during daylight hours in the next couple of days when you are sure that no animal has returned or is trapped inside (you will need to listen for several days, if the possum has been trapped inside, its noisy attempts to escape will alert you). Repairs need to be sound as possums' are quite strong and will work hard to re-enter their shelter site. Young possums always ride in their mother's pouch or on her back.
Once the possum no longer has access, wash the old entry areas with a strong smelling substance such as disinfectant or bleach, to disguise the scent trails and prevent other possums following.
Undertake preventative measures to stop access to your roof, for example, remove branches from trees that provide access; use metal flashing to make a disc to place around pipes to prevent them climbing, or place broad metal bands around support beams for structures that they may climb for access. Possums may also be attracted to your property by open compost in which they may scavenge for scraps or for cat and dog food left outside. A closed compost system and the removal of cat and dog food overnight may make your property less attractive to them.
Possums can be encouraged to stay in your yard, and not in your roof, by providing a nesting box (see diagram next page) or hollow log blocked at one end. It should be waterproof and placed four to five metres above the ground.

2. Possum-proof fencing

Floppy-top extension to an existing fence.

Brush-tailed possums readily climb fences but many can be possum proofed. Possums can only jump about one metre vertically and cannot climb sheer walls. Therefore, a well-made tin or paling fence (with the frame on the inside and the palings butted but not overlapped) about 1.5 m high will keep them out. Wooden fences will of course need a tin section - at least 33 cm wide and 80 cm from the ground - around the corners. A simple 'floppy-topped' fence has proved very effective against possums climbing over ordinary fences. The fence is fitted with a netting top (chicken wire) that overhangs on the outside. As the possum (or cat or quoll) attempts to climb the overhang, it bends down and the possum will let go and fall to the ground. The floppy top then springs back to the original position (it is set on high tensile wire) ready for another assault.

Trapping

Trapping and relocating the animal does not generally work - not just because the brush-tailed possum may find its way back but because when a home range becomes vacant, another possum moves in. Active possums are strongly attached to their home range and those which have been removed and relocated, may face a slow death, either because the release area is unsuitable or another possum occupies it and will defend its territory vigorously. Competition for food and shelter usually means that the relocated possum dies. All species have specific habitat requirements for their survival.

A study by Deakin University in Melbourne (Pietsch 1994) found that the survival rate of possums relocated from an urban environment to a rural/bush environment was very low and the majority died within a week from predation or as a result of the relocation outside of their normal home range. Active possums are territorial and the survival skills they develop to live in an urban area are quite different to those skills required to live in a rural/bush environment.

As a last resort a permit can be issued to trap. These permits contain strict conditions on the type of trap to be used and what may be done with the animals.

For primary producers of crops and pasture who are experiencing browsing problems from possums, crop protection (spotlight) permits are available on application to the Department of Natural Resources and Environment, Wildlife Services, by phoning (03) 6165 4305.

Possum nesting box

Drawing of a possum nesting box.

The top edge of the roof should be weather sealed with a folded strip of sheet metal, aluminium angle or a rubber flap. (An old rubber inner tube is OK).

To stop rain getting in, eaves should overhang by 110mm to 120mm. The entry hole (which doesn't have to be round) should be located directly under it and be between 110mm to 120mm wide.

A sturdy length of branch screwed firmly to the front of the box is an optional extra that will help the possum enter and exit more easily.

Drill four holes (approx 5 mm) through the floor near each corner, to allow any water that might get in to drain out. Some nesting material (dead leaves, natural wood shavings) would provide extra insulation. Do not use chipboard, as it will disintegrate quickly.

Possums and gardens

If planning a garden, try to select plant species, which are unpalatable to brush-tailed possums such as prickly and spiny grevilleas and hakeas; tough and woody banksias and melaleucas (tea-tree) and plants with smelly foliage such as chrysanthemums, mint bushes, geraniums and daisies.

Roses and fruit trees can be browsed unless protected. Repellents, fencing and netting can be effective. Trees can be protected by attaching a broad 40cm band of metal around the trunk at least 50 cm above the ground.

Injured and orphaned brush-tailed possums

Injured or orphaned brush-tailed possums are often found and there is a network of carers available to rehabilitate and release these animals. For assistance contact the Wildlife Services Branch.

Handle with care

Remember: brush-tailed possums are wild animals and although they look cute and cuddly they can bite and scratch severely, especially when injured or afraid.

Wear protective gloves or restrain the possum in a blanket or towel if you need to handle it.

Possum conservation

Brush-tailed possums along with other types of wildlife benefit from retaining areas of natural bush on your land and placing nest boxes in your garden. Keeping cats and dogs inside at night, covering up the compost bin and not leaving pet food out at night time.

Possums are a part of suburban living and are not shy of humans. They provide a wonderful link between urban people and the natural world. Their antics and acrobatics are a delight to watch at night.

While possum populations are relatively stable at the moment, the effects of land clearing, road kill and cat and dog attacks can have a detrimental effect on their population and has elsewhere in Australia.

The Wildlife Management Branch is monitoring possum populations by conducting regular surveys around the State.

Further information

Kerle, A. Possums, The Brushtails, Ringtails and Greater Glider. UNSW Press.

Smith, B. Caring for Possums. Kangaroo Press.

Strahan, R. (ed) (1995). The Mammals of Australia. Reed Books, NSW.

Temby, I. Wild Neighbours Citrus Press

Thanks to the A.C.T. Parks and Conservation Service, for use of artwork and information from their Living with Possums brochure and also thanks to Native Animal Network Association Inc. (NANA) for their use of the Possum nest box design.