Authorities and wildlife carers warn residents against providing meals for their visiting wild feathered friends to discourage human dependency and help prevent the spread of infectious diseases, such as the common virus Psittacine beak and feather disease.

"Like many viruses close contact can cause beak and feather to spread rapidly and WIRES always encourages residents to please not feed any native birds," a spokesman for wildlife rescue group WIRES, John Grant, said.

At least one Blue Mountains resident, who the Gazette has chosen not to identify, has been referred to council over allegations rat infestations, thousands of dollars in property damage, and increased avian disease risks are the result of "irresponsible", regular and substantial sulphur-crested cockatoo feeding.

"It is not unusual to see around 30 or so birds in this group," one neighbour wrote in a statutory declaration outlining her concerns.

"This creates an incredible and deafening noise that makes it unbearable to be outside."

READ MORE:

Among other accusations from neighbours were that cockatoos had stripped outdoor furniture, decking, windows and trees.

While there is debate, most wildlife groups and government bodies discourage wild bird-feeding.

But Councillor-elect Romola Hollywood said state standards should be clearer.

"We're almost killing these animals with kindness," she said.

"It would be great for the State Government to introduce some laws or [a] public education campaign that gives more information about the pros and cons of feeding our wildlife and highlights that feeding some birds may be actually causing them harm.

"The NSW Government does not have an overarching law that says you can't feed wild birds."

Sulphur-crested cockatoos, found across eastern and northern Australia, are a common and raucous feature of Blue Mountains life.

Like other native parrot species they are susceptible to viruses and bacteria.

The most common of these, the beak and feather virus, stops normal feather growth and can cause the beak to distort, sometimes leaving bones exposed.

It's progressive, usually fatal, and is spread easily through shared food, excrement, and feather and skin particles.

"The infection results in abnormal feather development and misshapen beaks that can break and cause the underlying bone to be exposed and severe infections to develop," University of Sydney veterinary medicine professor David Phalen said.

"The virus also attacks the immune system so these birds then become susceptible to secondary infections."

Native bird rescues are on the rise in the Mountains.

Recorded rescues leapt from 605 in 2017-18 to 2035 in 2019-20.

Confirmed beak and feather disease made up a very small proportion of these, but most reasons were unknown.

A spokeswoman for Blue Mountains City Council said bird feeding was raised from time to time and there wasn't much council could do.

"While the feeding of birds is not specifically prohibited on a residential property, occupants are required to maintain a minimum health and amenity standard," she said.

"The feeding of native birds is not an activity that is enforceable by state government legislation and, as such, council has no regulatory authority to enforce the ceasing of the feeding of birds."

WIRES said native birds' natural diets do not usually need to be supplemented.

But if people wanted to attract birdlife to their gardens the best way is to plant more native trees.

"Grevilleas and Callistemons will ensure nectar-loving birds such as rainbow lorikeets will be regular visitors," WIRES spokesman John Grant said.

Seen an injured or sick wild animal? Contact WIRES on 1300 094 737.