Native birds visiting your backyard or balcony can be a welcome sight, but avian experts say feeding them may be doing more harm than good.
NQ Wildlife Care, a Townsville-based animal rescue group, said it was receiving more calls than usual about birds suffering from psittacine beak and feather disease (PBFD).
The highly contagious and incurable virus causes feather loss and beak deformities in parrot species.
NQ Wildlife Care's Katelin Hasenkamp said most of their callers did not understand how serious the disease was.
"It's a long, slow death," Ms Hasenkamp said.
"Once they have it, there is nothing you can do, and they continue to spread it around to the rest of the flock … especially if they're feeding in backyard feeders.
"Those feeders can carry the disease for a number of years … so backyard feeders are pretty dangerous in that respect."
Two sick cockatoos reported to NQ Wildlife Care in Townsville. (Supplied: NQ Wildlife Care)
'HIV of the bird world'
University of Queensland avian medicine expert Professor Bob Doneley said the disease was spread through a parrot's droppings, feather dust, sneezing, and coughing.
"We call it HIV of the bird world," Professor Doneley said.
"This virus attacks and destroys the immune system so the birds are very susceptible to other infections.
"The estimates are that 30 per cent of the wild flock of cockatoos has this disease, so it's a very common problem."
Visitors to Hamilton Island in the Whitsundays regularly raise concerns about sick cockatoos.
Professor Doneley said there was no commercially available vaccine for PBFD.
Psittacine beak and feather disease causes healthy birds to lose their feathers. (ABC: Ann Jones)
"No vet tries to treat this virus — we euthanase them on diagnosis because once they've got this disease there's no cure for it," Professor Doneley said.
He said the virus was seen as a "thinning of the herd" and there was no government effort to control the threat.
How to help
NQ Wildlife Care said people could try to gain the trust of sick birds in order to capture them and take them to the vet.
But Professor Doneley said that could be a tough ask.
"You can set up traps but you're going to catch healthy birds as well as infected birds and, if you've got them all in one trap, the healthy birds aren't going to be healthy for much longer," he said.
"Even catching a wild bird like this and transporting it to a veterinarian, while it sounds good is unbelievably stressful to the bird."
Psittacine beak and feather disease is a death sentence for parrots. (Supplied: NQ Wildlife Care)
Professor Doneley said the best course of action was to stop the parrots from gathering in groups where the disease could spread.
"Public feeding shouldn't be done — don't feed these guys in your backyard, don't encourage them to come together," he said.
Despite a "grim outlook" for the afflicted parrots, Professor Doneley said some could survive for years.
"I have one that I see on a regular basis that's had this disease for over 10 years, so he's beating the odds," he said.
"He's got virtually no feathers and no top beak but he's as happy as Larry. His owners dote on him and he dotes on them."