Wood pigeons are gorging themselves on a bumper crop of summer fruit - to the point they're getting drunk and falling from trees.

Locals in South Westland are being asked to keep an eye out for the intoxicated kereru, New Zealand's native wood pigeon, and help them sober up.

Forest & Bird experts say when kereru gorge themselves they sit in the sun for long periods to digest their food.

And if the fruit is ripe and the weather is warm, it can ferment in their crop - an internal pouch that's part of their digestive system - and turn into alcohol.


"It's cheap way of getting drunk isn't it," said kereru expert Ann Graeme.

The Native Bird Recovery Centre in Whangarei said because it had been a "really good" fruit season on the West Coast, there will be large numbers of kereru putting themselves in danger by going over the limit.

In 2010, the sanctuary was inundated with about 60 wood pigeons who'd had too much guava.

"They were coming in absolutely drunk as can be," said manager Robert Webb.

"It was ridiculous, we were getting people bringing armfuls of these flaming drunk pigeons."

He would keep them for three or four days to ply them with basic food to sober them up.

While it was humorous to witness, Mr Webb said by falling from their perches, kereru can injure themselves or become prey for predators, like cats, dogs, or stoats.

"They don't have a feed, fly away and get drunk, they go to (their equivalent of) the local pub, and get on the booze till they can't walk any more."


He asked South Westland residents to be aware that a drunken wood pigeon might need assistance and to alert local authorities.

Kereru have been seen in high numbers in the district this summer as they flock to the bountiful bush fruit.

"Just around my place there are 30 to 40," said Bruce Bay resident John Birchfield.

"It's the most I've seen in my eight years here, they usually disappear before now.

"They were here early, too, feeding on our new willow shoots. They moved on to kowhai, and are now on the miro trees, and wineberry bushes."

Anne McSweeney, from the Lake Moeraki Wilderness Lodge, said kereru had been doing "magnificent, sweeping displays".

The high number of birds could make things interesting for those participating in the second annual nationwide Kiwi Conservation Club kereru survey, which starts on Sunday.

New Zealanders, young and old, are asked to visit gardens, parks and reserves and count the number of kereru they see.

The data can then be lodged on the Kereru Count website, including the number spotted, what the kereru are doing, and, if possible, what type of plants they are feeding on.

The survey runs to March 4.