Sydney's prime waterfront real estate is being overrun by squatters looking for free food.
Cockatoos are flocking to urban areas and city parklands where food scraps left by people are plentiful and waterfront roosts abound.
Favourite roosts for Sydney's sulphur-crested cockatoos include Cronulla, the Royal Botanic Gardens and Rushcutters Bay.
Australian Museum ornithologist Richard Major says there has been "no major migration for cockatoos although [they have] been breeding up more in number".
The first Birds in Backyards survey found they were the fifth most commonly reported bird species in Sydney, recorded in 60 per cent of gardens.
Parrots and cockatoos have a strong cognitive ability and have become "winners of urbanisation" as they have adapted to thriving off resources such as food waste discarded by people.
Working with Royal Botanic Gardens, the University of Sydney and the Australian Museum, Dr Major is running a project, Wingtags, that studies cockatoo behaviour.
In the past four years more than 100 sulphur-crested cockatoos, Cacatua galerita, have been tagged and tracked across Sydney.
The project has found Sydney's birds belong to four major social networks in the city, each with its own unique behaviours for communicating and looking for food.
Sydneysiders have been told to expect more cockatoos as the birds hone their food scavenging skills.
Retrieving food from rubbish bins is a newly learnt behaviour that continues to fascinate researchers, with birds able to open the lids of closed wheelie bins.
A cockatoo was caught on camera opening the kitchen window of a Mosman home in 2015.
Acknowledging that large numbers of cockatoos and other birds are sometimes perceived as pests, Dr Major said we need to "be more tolerant [and] learn to live with the birds that are sharing the environment with us".
Touching or hand-feeding is not recommended as some may carry disease as well as bite.
If you see a tagged cockatoo or a bird behaving unusually, Dr Major recommends contacting the Wingtags project.
This article first appeared on the Sydney Morning Herald.
