Pet birds like this scarlet macaw at Bird Barn don't fare well if released in the wild. Photo: RNZ / Finn Blackwell
Auckland Council fears large numbers of exotic birds are posing a threat to the local ecosystem.
A University of Auckland study found nearly 500 pet birds go missing each month.
Exotic birds have been spotted across Auckland and the city council's Dr Imogen Bassett said pet parrots in particular were finding their way into the wild.
She wanted to stop pet bird species from establishing wild populations.
"Internationally, we know the pet trade is a really major driver of new vertebrate pest invasions.
"So we've got this opportunity here to prevent a future problem with respect to parrots."
There were many potential consequences of pet birds flying the coop.
"They can spread disease to our native bird species, and they also might compete with them, so we know that they can be quite aggressive and confident, and bully our native species away from the food sources that they want, and from their nesting spaces," Bassett said.
"Some of them will strip bark off of native trees, that sort of thing."
Species like Indian ring-necked parakeets, monk parakeets and rainbow lorikeets have restrictions around sales and breeding.
Bassett said there were rescue centres in Auckland where bird owners could take pets to be rehomed if they could no longer take care of their pets.
"We have a number of rescue centres in the Auckland region that are allowed to receive animals, and, absolutely, we want people to be doing the right thing, so there's no barrier to people doing the right thing."
She encouraged owners to be responsible and make sure their pet could not get out and take off.
"We hear all the time from people saying 'It's not my pet, my pet wouldn't do that,' but actually, the stats say otherwise, really clearly," said Bassett.
"For the wellbeing of your pet, and also for our wider environment, please make sure you keep it contained."
In West Auckland, Karl Williamson from the Bird Barn Pet Store said most exotic birds did not survive long in the wild.
"There's a budgie in the back room that someone found the other day, and it was probably about a day away from being dead.
"Birds generally when they get out into the wild do not survive if they're out for any period of time, because they're used to eating food out of a little green cup, so if they get out, they don't know how to find their own food and they often end up going to ground, which is generally, a cat will pick them up."
Williamson said it was not too difficult to look after a pet bird, depending on its size.
"A smaller bird, like a budgie or something, is not too bad, as long as you keep the cage clean and fresh water and food every day, and a bit of attention.
"Something like the bigger parrots, like the macaws or the black cockatoo, need plenty of daily attention like a dog or a cat would."
Williamson said most bird owners had ways of keeping their pets contained.
"Most people with aviaries will run a double door, which means you basically have a door you have to go through and lock behind you before you go into the main aviary, so if a bird does get out the door, then you've got a little space to usher them back into the main aviary."
Clare Stringer from the Department of Conservation said pet birds on the loose were not just an Auckland issue - wherever there were people, there was the problem.
"The pet bird issue is an issue of humans.
"Most of the issue is in Auckland, and then other major centres do also see these escaped pet birds as well."
She also advocated for responsible bird ownership.
"They're very beautiful, and the best place for them is with their humans,
"We would say just take care of them and don't let them go."
The Ministry for Primary Industries said pets released into the wild could compete for food, introduce diseases, and become pests of cereal and fruit crops.
It said they could nest in city buildings and cause damage, but that they were unlikely to pose a significant biosecurity risk.
"Several regional councils and unitary authorities have listed pets as pests in their Regional Pest Management Plans in an effort to limit the spread of the species by making it an offence to sell or to deliberately release them into the environment, as well as giving the council power to deal with any pest pets found in the wild," said Biosecurity New Zealand Director of Pest Management John Walsh.
"Eastern rosella, sulphur-crested cockatoo and rainbow lorikeet are examples of birds that have been identified in regional pest management plans."
He said Biosecurity and regional councils had a good working relationship with TradeMe to monitor the sale of unwanted species, and in most instances, listings are removed and sellers are provided information on the regulations of species, and that they cannot be bred and sold.
SPCA scientific officer Dr Alison Vaughan said people could report escaped pet birds on the New Zealand Companion Animal register, as well as social media.
"If you find a bird that is injured or shows obvious signs of sickness, then you should contact your local veterinary clinic or, alternatively, call SPCA for advice or additional information.
"If you have assessed the situation and you have decided that there is a need to rescue the bird immediately, call SPCA or your local bird rescue for advice on how to contain the bird."