Biosecurity officials are appealing to the public to help them track down a large number of angry birds on the loose in Auckland.
The Ministry for Primary Industries (MPI) has confirmed red-vented bulbul have been spotted in Mangere, Devonport and possibly on the Whangaparaoa Peninsula.
It's uncertain how many ofthe birds are out there.
MPI Response Manager Jaap Knegtmans said red-vented bulbul are aggressive pests that have developed a reputation as one of the world's most invasive birds.
There are concerns the bird will damage Auckland's horticultural industry, native vegetation, birdlife and private gardens.
Red-vented bulbuls have invaded other parts of the Pacific, including Fiji and suburban Sydney, and may have hitched a ride to New Zealand on a commercial vessel or recreational yacht, Knegtmans said.
They have been found in Auckland before - in the 1950s and more recently in 2006. In both instances they were eradicated.
Red-vented bulbuls are a medium-sized bird around 20cm in length from body to tail.
They are generally dark coloured with a lighter chest and rump, a small crest on their head, and significantly, a very distinctive crimson-red patch beneath their tail.
The red patch was the bird's key identification feature, Knegtmans said.
If you see a red-vented bulbul, contact MPI on its free Exotic Pest and Disease Hotline - 0800 80 99 66.