Possums are nocturnal, which means that you won't realize that your walls are harbouring them until you are about ready for bed. Hearing the thump and scrape of a possum or two as they manoeuvre their bodies throughout your house, sometimes just inches away beyond the plasterboard, can be irritating and distressing.

While possums are extremely territorial as well as persistent when it comes to their nesting site, with a little patience, you can remove them without causing too much fuss.

Do Not Use Poison

Possums are a protected species in Australia, and you won't be granted a permit to eliminate them unless you have proof that you have tried every other otherwise humane method at your disposal. Therefore it is illegal to poison possums.

Furthermore, if you do place poison in your roof space, be prepared for an unpleasant stench that may last weeks, especially in hot weather.

Determine If the Animal Is Stuck or Not

Your first course of action should be to determine if the possum is stuck or not. This happens when possums enter your home through a hole in the roof and then fall down inside the wall. With no way to get back up, they'll scratch frantically at the plasterboard wall in an effort to get out.

If the noise is confined to one spot, you likely have a possum stranded inside your wall.

In this case, you will need to call out a pest removal expert who can then cut through the wall to remove the possum before it dies.

Locate Access Points on the Roof

If the scratching and thumping moves around, especially at night and usually ends over your head, the possums are free to go as they please (much to your dismay!).

As possums are nocturnal, they leave their nest at night to go in hunt of food. This is your chance to find out how they are getting in. Wait until you hear them leave and then, as carefully as you can, get up to the roof and locate all access points.

Possums are crafty and very good with their hands so, even if you don't see any obvious entry points, they may have found their way in by lifting up a loose roof tile, or via a small gap between the ceiling and roof.

Place a Possum-Box Filled With Treats in a Nearby Tree

Don't take action just yet. You first need to purchase a possum-box—which will serve as their new home. The next day, purchase a possum-box, locate a nearby tree and place the possum box. Don't fill it with treats just yet, however.

Wait for the Possums to Leave Their Nest

At about the same time as the night before, the possums should leave their nest in your wall to go in search of food. Now is your chance! Go outside, fill the possum-box with treats such as honey-coated banana, and some nuts, fruits and grains to entice them to enter the box and make it their new home.

Seal All Access Points

Go back up to the roof and seal all entry points as thoroughly as you can. Remember, possums are persistent and will try to get back in. Sprinkle some naptholene flakes (found in mothballs) around the access point for good measure. Possums can't stand naptholene.

If all goes well, your possums should return to the nest, find it blocked, and then go in search of somewhere else to stay for the night. Upon finding the possum-box, the plan is that they will be enticed inside by the treats and sufficiently impressed to make the box their new home.

Remember, though, that possums are almost fanatical about their nesting sites and may very well attempt to force their way back inside. If your best laid plans fail to evict them, call on the professionals to get the job done. Pest removal experts like Allstate Pest Control have the tools, the techniques and more importantly, the experience, to rid you of those possums in your walls.