Brush turkey numbers plummeted in the 20th century, largely due to land clearing. During the Depression, Sydneysiders ate them. "A grandmother who remembers eating them as a child said they were very tough and stringy," a National Parks and Wildlife Service officer told the Herald in 2009. More recently their return has been linked to the trend towards native gardens in our suburbs. A decade or so ago, the turkeys emerged on the Central Coast and northern beaches. Since then, they've moved into most of the northern Sydney suburbs and are now spreading into new areas. Matthew Hall, a PhD student at The University of Sydney, has recently collaborated with The Royal Botanic Garden and Taronga Zoo to study the increase in brush turkeys in Sydney. "Part of our project is to study how they're surviving so well in the city and suburbs - what behaviours are allowing them to thrive and spread," Mr Hall said. "Our research involves wing tagging and GPS tracking turkeys to see how they're moving in and surviving in the city and suburbs. We're hoping to answer several questions including what is their population size, what is driving the population increase and their movements, and what effect they have on the environment."

However, Dr David Wells from Macquarie University who has studied brush turkeys, says the recent increase can be traced back as far as the Depression, where they were hunted for food and eventually disappeared from the Sydney region. "They are recovering territory they previously occupied. Brush turkeys were almost certainly here when Europeans first arrived but they seem to have gone locally extinct around the Depression, because they were hunted," Dr Wells said. "Laws against hunting native animals in the 1970s have shifted the balance in favour of these birds." Brett Davis, from Birdlife Shoalhaven, says the turkeys can adapt to humans and become unafraid and even aggressive in places where the public give them food. "They will steal food from tables, bags and bins and can become a real nuisance around picnic areas. They are big birds, with big bills and big powerful legs and feet, so they do have the potential to hurt people," said Mr Davis.

Experts say local councils can't do much to curtail the birds as it's illegal to harm or trap brush turkeys without permission. Homeowners can discourage them from digging in the garden by covering areas with large stones or chicken wire. Also, if you see a brush turkey nest you should clear it as long as there are no eggs in it. "My advice is if you see a male just starting to build a mound then it's fine to clear it and he'll move along somewhere else," Mr Hall said. "But if you leave it too long he'll keep coming back, even if you clear it. You can also discourage brush turkeys by spraying them with a hose as well. This doesn't hurt them but makes them move on." And it looks like we will be seeing them a lot more. Mr Hall says despite the project being in its early stages, the success of the turkeys at moving back into the city, which is a hostile environment for most animals, has been remarkable. "I'd expect the brush turkey population in Sydney will keep increasing unless something major changes, and we'll be seeing them in new suburbs soon. People living in the inner west and eastern suburbs should expect to start seeing more brush turkeys soon."