Across Australia, councils are grappling with how to control large flocks of corellas which are increasingly settling year round in city parks with rolling lawns and water features. A large flock of Corella arrive in Terara at sunrise from nearby Nowra Credit:LOUISE KENNERLEY Most are Little Corellas (Cacatua sanguinea known as the Blood-stained Cockatoo). Nowra's flock appears to include Long-Billed and Little Corellas. There are historic records of birds sliding down rooftops and swinging from windmills, said Dr Richard Major, a principal research scientist and an ornithologist at the Australian Museum. It was very difficult to interpret this as anything other than play and curiosity, he said.

Like parrots, the corellas - who belong to the cockatoo family - were big-brained birds, which are "as smart as your average two year old". A flock of Corellas in Nowra Credit:LOUISE KENNERLEY Not seen in Sydney or urban areas before the 1950s, their intelligence probably explained why the birds had moved from semi arid areas and adapted to novel environments, he said. 'Darn it, I've created a luxury resort for little corellas'

A 2018 report by academics at the University of South Australia said the problem was not the corellas but city planning. "We have created a perfect habitat for little corellas and they are taking us up on the offer". Corellas in Nowra's Marriott Park. Credit:LOUISE KENNERLEY In a section titled, "Darn it, I've created a luxury resort for little corellas," a land manager realised he had created a perfect environment for birds with wide-open lawns skirted by a few tall trees and an easily-accessible water source. He recommended solutions, including planting more shrubs, to discourage the corellas.

Authors Philip Roetman and Annette Scanlon said the abundance of these birds in towns was a sign of an impending problem. "We are in danger of excluding all but a few species of bird from our towns and cities. We will miss the variety of birds and bird songs that beautify our urban landscapes," their report states. Loading "We will be left with families and flocks of birds that are often large, loud, annoying or destructive. In particular, white ibis and noisy miners are massive winners in urban parks." Dr Major agreed that increasing shrub cover was important for preserving bird diversity, but he wasn’t confident that it would reduce the number of corellas.

There was no comment from the Shoalhaven Council, although locals squawk as loudly as the birds about the noise and the mess. "They're supposed to be a pest, and they do a lot of destruction to the trees," said Tania Osborne, who owns the Cockatoo Cafe near the park. They were very noisy early in the morning and even at 9pm at night she could hear them. "I'm always sweeping feathers away," she said. Like many, Ms Osborne found it hard not to like them. "I have even seen them in the park, rolling around upside down playing on the ground."