One of Australia's largest species of cockatoo, the yellow-tailed black cockatoo, is hard to miss.
It's loud, with a distinctive screech and a gently undulating movement in flight.
Bird lovers on the New South Wales Mid North Coast have recently been noticing large numbers of the native species in the region.
"Whenever there's an increase in black cockatoos everyone notices, as they are so beautiful and large and raucous as they fly along," said Birdlife Australia's NSW woodland bird program manager Mick Roderick.
"They are so big, the way I describe their flight is that they 'swim' through the air … they actually remind me of a turtle moving under water.
"They just slowly, gracefully beat their wings and their long tail seems to hold them afloat."
Mr Roderick said that during a recent holiday on the Mid North Coast he observed a high number of yellow-tailed black cockatoos, including one strikingly large flock passing over the town of Urunga.
"I did a walk out to the Urunga pier and back and I counted 310 black cockatoos going past, over a period of about half an hour," he said.
"It's the largest flock I have ever seen and seeing more than 300 black cockatoos pass over was absolutely amazing.
"They were moving in small groups to form this overall large flock … it was a very special sight."
Mr Roderick said he hoped it was, in part, a sign of a healthy breeding season.
"All the birds were flying north and all mainly in pairs or groups of three," he said.
"I think that might suggest that the groups of three are parent birds with a young one in tow. I was heartened to see that amongst this really large flock."
Looking for food in urban areas
Mr Roderick said it was possible the black cockatoos, which eat the seeds of trees and shrubs, as well as insect larvae, had moved more into urban areas in search of food.
"I think the most likely explanation is that something is going on with their natural food sources," he said.
"They are normally in a more natural environment seeking out things like banksias, but if things like that aren't available, they will move into the town to seek out food sources.
"They're quite adaptable and will feed on planted trees, even pine trees and things like that."
He said changes in natural habitat and urban expansion had influenced the behavioural patterns of certain bird species.
"Usually what happens in the summer months is the black cockatoos would mostly be up in the mountains, you wouldn't get that many down on the coastal plain, things like currawongs are the same," he said.
"But over the years, as food sources have changed, and we are growing things in towns that appeal to these birds, some birds have changed their seasonal movements."
Black cockatoos also feed on grubs in trees, and can cause significant damage, sometimes leaving property owners scratching their heads.
The yellow-tailed black cockatoo, Australia's biggest endemic cockatoo, is found across eastern and southern parts of Australia, from South Australia's Eyre Peninsula to Queensland.
Mr Roderick said the species' numbers were secure at the moment, but it was important to ensure their habitat was not reduced.
"They need enormously large hollows … a similar sized hollow to an owl," he said.
"So, if we do start losing more of our hollow-bearing trees they could easily decline very quickly."
'Vulnerable' glossy black cockatoos
Yellow-tailed black cockatoos are one of two species of black cockatoos found in NSW. The other is the much less common south-eastern glossy black cockatoo.
It's a species in decline, particularly after losing crucial habitat during the severe bushfires of 2019/2020, and was listed as vulnerable nationally in August 2022.
"Unlike yellow-tailed black cockatoos, glossy black cockatoos are habitat specialists," Mr Roderick said.
"They specialise in just eating the fruits of casuarinas, or she-oaks, which occur in natural areas that were really badly burnt in the bushfires."
Birdlife Australia, the NSW government, an Aboriginal advisory group and other conservation groups are all working to try to boost numbers of the glossy black cockatoo.
"There are projects underway trying to work out what's going on with the populations and their breeding habitat, and breeding behaviours, so we can work out where they are and how we can help them," Mr Roderick said.
