ROOF & WILDLIFE
Possums in the roof after Sydney's spring winds: how to tell them from rats and get them out legally
Heavy, steady footsteps in the ceiling after a windy, cold spring night are often a possum, not a rat. Possums are protected native animals, so the way out is humane and specific - let the animal leave, then seal the gap the wind opened.
After a blustery Sydney spring day with a Marine Wind Warning and overnight temperatures down near nine degrees, it is common to start hearing movement in the roof at dusk. Before assuming rats, listen properly. A rat makes a light, busy scurrying and gnawing sound; a possum sounds like heavy, slow footsteps, sometimes with a thump as it lands, and grunting or hissing chatter. The difference matters a lot, because the two problems are handled in completely different ways - one is a pest treatment, the other is a protected native animal that must be let out, not killed.
Why wind and cold nights bring possums overhead
Brush-tailed possums are already in nearly every Sydney street, living in tree hollows, roof spaces and dense foliage. A gusty spring day widens the routes they use. Branches scrape and loosen tiles and flashing, eave openings get bigger, and a cold night makes the warm roof cavity more attractive than a draughty tree. Because they are territorial and return to the same den each morning, once a possum finds a comfortable roof space it tends to keep using it. Spring can also mean a mother with a small possum riding on her back, which changes the timing of any eviction.
Possum or rat: how to tell the difference
You rarely see either animal, so the sounds, the timing and the droppings are the clues. Listen for a few evenings before acting, because the treatment path depends on getting this right.
Possum: heavy, slow footsteps and thumps, mostly around dusk when it leaves and before dawn when it returns.
Rat: light, rapid scurrying, scratching inside walls and gnawing, at any hour and often through the night.
Possum droppings are larger than a rat's, dark and often in piles near the entry point; rat droppings are small, pointed pellets scattered along runways.
A strong, persistent ammonia smell and dark stains on ceilings or downpipes point to a regular possum den.
Why you cannot treat a possum like a rat
Possums are protected native animals under NSW law. Harming or poisoning them is illegal, and catching and relocating one is regulated rather than left to the householder - a possum released away from its territory usually does not survive. Spring in particular can mean young in the roof; sealing a mother out while a joey remains inside is both cruel and unlawful. This is why laying rat bait in a roof that actually holds a possum is a serious mistake, and why identification comes first.
The humane way out: let them leave, then seal
The accepted method is a one-way door, sometimes called a possum flap: a device fitted over the entry point that lets the animal leave at dusk to feed but stops it coming back. Timing and sealing are the whole job.
Confirm first that no young are trapped inside; when in doubt, a licensed wildlife rescue group such as WIRES should check.
Fit the one-way door on the entry point at dusk, over several nights if needed, so every animal leaves.
Once the roof is empty, seal the opening with possum-proof materials - sheet metal, mesh or solid timber around the eave and vent.
Offer a nest box in a nearby tree and trim branches away from the roof, so the possum has a legal alternative den and fewer routes back.
What to fix after the wind, and when to get help
While the possum is still using the roof, do not close the access. Once it is out, check the outside of the roof the same way you would for rodents: shifted tiles, lifted flashing, torn eave mesh and branches touching the roofline. A pest technician who works with wildlife can fit the one-way door, verify the roof is empty, and seal the entry points, and will bring in a wildlife rescue group if a joey is involved. If you are unsure what is overhead, it is worth having the roof identified before buying any product.
Never use rat bait or traps for a possum - protected wildlife cannot be poisoned, and a dead possum in a wall cavity also creates a serious smell and a fly problem. When it is genuinely a rat, use only registered rodent products in locked tamper-resistant stations, following the current label as the APVMA explains correct chemical use.
HEARD HEAVY FOOTSTEPS OVERHEAD?
Text your suburb and what you have heard.
Tell us whether it is heavy thumps at dusk or light scurrying through the night, where the sound is, and whether you have found droppings or a roof gap after the wind - we can tell you whether it is possum or rat, and what is worth doing.