Yellow-Tailed Black Cockatoo has been been carrying an extra load for five years

Greg Tannos, who lives nearby, photographed and videoed the male cockatoo for his website findmyaustralia.com

"The cockatoo was in a small flock happily feeding on Banksia pods in the bushland around Georges River National Park," Mr Tannos said.

"It surprises me that the tag is still on after five years.

"While the bird seems to have outgrown the belt/strap, which has damaged his wings, he looks strong and healthy."

Dr John Martin, a research scientist with the Taronga Conservation Society who led the study, said "the transmitter could come off at any moment, especially if the bird wants to remove it".

"The now loose shoulder-straps are designed to fall-off over the wings," he said. "The cockatoo can assist this process but it appears it hasn't figured this out.

"Similarly, we've seen other cockatoos chew through the material harness, so this bird could quickly remove the transmitter if it tried.

"This was the first study into the movements of Yellow-tailed Black-Cockatoos using GPS tracking. We observed birds move from Sydney to Jervis Bay, the Southern Highlands, Windsor, and the Central Coast, indicating that birds move into the city to forage during winter on abundant pine cones from up to several hundred kilometres in all directions."