A single sighting of an invasive animal on the outskirts of Australia’s largest city has triggered a surge of reports, as residents come forward in droves to reveal just how widespread the destructive pest is.
This week, Sydney MP Simon Kennedy shared a video of a huge deer in Gymea Bay.
The mature animal is seen rummaging through suburban properties, likely in search of food, undeterred by the presence of nearby people in a car.
Experts warn that sightings like this are no longer isolated. And locals agree.
“I’ve seen deer swim across the Hacking River from Royal National Park to Swallow Rock at Grays Point,” one man said.
“They seem to come more into the streets in cooler or rainy weather,” said another.
“There are heaps in Gymea,” wrote a third. “I see them all the time late at night,” another resident echoed.
It comes as Australian communities continue to grapple with the devastating impacts of introduced and invasive species, which outcompete their native counterparts and smother vulnerable ecosystems.
Foxes, pigs, cats and rabbits are just a few that have wreaked havoc since being introduced by Europeans, and in large parts of the east coast, deer are emerging as a drastically worsening problem.
Experts say the animals are becoming more brazen and more widespread. Source: Tim Kennedy
Are deer becoming more common?
Deer and other invasive species are increasingly venturing beyond their usual forested or park habitats, establishing themselves in suburban streets, school grounds, and even gardens.
Residents, not just in Sydney but around the country, have recently reported animals browsing backyards, overturning bins in search of food, and moving freely along roadsides.
This shift reflects not just growing numbers, but a behaviour change.
Where once deer were largely confined to bushland, they are now exploiting suburban environments, attracted by easily accessible food and fewer natural predators.
A deer was recently spotted on train tracks in Eastwood, Sydney. Source: humansofeastwooddaily/Instagram
Where are deer a problem in Australia?
Across Australia, deer are found virtually in every Australian jurisdiction.
CEO of the Invasive Species Council, Jack Gough, recently spoke to Yahoo about the worsening issue, saying it used to be “unusual” to see deer “deep into suburbia”, but it’s now becoming increasingly common.
“It’s a problem in Melbourne and a growing issue in the Gold Coast and Canberra,” Jack said.
“Adelaide is trying to remove them from the hills before they get out of control there.”
Jack pointed out that in NSW, according to the Greater Sydney Regional Pest Strategic Animal Management Plan, deer are “moderately distributed” across the city, meaning there may be a chance to contain the spread if swift action is taken.
Wildlife specialists say this intrusion makes management more challenging, as the animals are not only more visible but also more habituated to humans, increasing the risk of vehicle collisions and property damage.
In Tasmania, calls are mounting on governments to get deer numbers down.
“It’s really time for the Tasmanian government to take the deer problem seriously and commit to the resourcing and the funds we need to get the deer population under control,” Invasive Species Council Conservation Officer Dr Tiana Pirtle said this month.
A map of deer spread across Australia Source: Invasive Species Council
The Council shared new figures from the Royal Automobile Club of Tasmania (RACT), which recorded 122 deer-related insurance claims between 2021 and 2025, costing motorists almost $800,000 in repairs.
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