An animal hospital in Whangarei has been inundated with starving native wood pigeons, which are otherwise known as the kereru.
In the last six weeks the bird recovery centre has seen more kereru than they would in a year and the shortage of food has experts scratching their heads.
"This has been a disastrous year, we've had 40 native pigeons come in the last six weeks and we've lost about 20 of them," Robert Webb from the Bird Recovery Centre told 1 News.
It is rare to see a kereru in urban areas but now as they search for food, there are reports of kereru sightings in backyards.
It is believed that the tarere trees where kereru would normally flock to for food have been fruiting later than expected.
"The alternative food is pigeon wood berries and unfortunately high numbers of rats are taking out the pigeon wood berries," Department of Conservation's Kevin Hackwell said.
Mr Webb says the birds have been too weak to put up fight and will use their own reserves and body fat to keep them going.
"They've just run out of energy and can't fly anymore that's why they end up on the ground."