Brush turkeys are heading back into urban Sydney areas in droves, according to an environmental expert, and there is not much residents can do about it.

The Australian brush turkey, also known as bush turkey and scrub turkey, are part of the megapode "big feet" bird family.

They wreak havoc in beloved backyards by raking up dirt to make large incubator nests which can sometimes hold up to 56 eggs in one mound.

This is because one male brush turkey can breed with up to six females who can each lay up to 12 eggs.

The population of brush turkeys in Australia was severely reduced along the east coast in the 1960s after coming close to extinction during the Depression as they were easy to hunt for food.

Tips to deter brush turkeys Attract the bird to a less valuable area of your garden by building a compost mound in a shady spot

Attract the bird to a less valuable area of your garden by building a compost mound in a shady spot Peg chicken wire or a tarpaulin over your mulch pile to stop the birds using the matter for their mound

Peg chicken wire or a tarpaulin over your mulch pile to stop the birds using the matter for their mound Keep compost in a closed bin

Keep compost in a closed bin Place rocks around precious plants

Place rocks around precious plants Replace mulch with gravel on garden beds Source: Warringah Council

As a result, they became a protected species in the 1970s which made it illegal to shoot them.

"In the 1980s, they took over Brisbane and Sydney is about 10 years behind what happened up here," Professor Darryl Jones, deputy director of Environmental Futures Research Institute at Griffith University, said.

"Once they get into the city [they] work out there's a lot of food and they have a fair bit of protection.

"I'm surprised that they can survive with all the cats and the cars."

Brush turkeys run free in St Ives (left) and North Sydney. ( Supplied: Alice Bryant / Julien Droulers )

In 2014, Professor Jones reported brush turkey numbers in Brisbane had increased by 700 per cent in the past 20 years and that NSW could expect an "invasion" in the next two decades.

He said the lack of predators in Sydney such as dingoes had contributed to the "sheer numbers" of brush turkeys.

While brush turkeys have cultural significance for Indigenous communities, particularly in northern Queensland, and are valued for their large eggs, they can be a nuisance for many in Sydney, particularly residents along the northern beaches and the Illawarra region.

Male brush turkeys spend up to four weeks raking together a mound to incubate eggs. ( Supplied: Floss Rutter )

Former Central Coast resident Paul told 702 ABC Sydney that he had "an ongoing battle for years" with brush turkeys that built nests in his garden.

"We had plague proportions when we lived on the Central Coast, and now I'm trying to grow food and vegetables but I've given up growing seedlings," he said.

"They just completely dig them up. I'm just fighting a losing battle."

But Sydney resident Joy believed the birds should be embraced.

"Brush turkeys are part of nature and they're coming into urban areas because we're encroaching on their space," she said.

"I've been able to successfully have a flower garden and a veggie garden and have brush turkeys wander through the yard ... the way I've done it is to have eucalyptus sticks and just put them in the ground around the plants.

"I haven't had any problems at all and people need to think of ways to overcome these problems rather than eradicating animals."