A plump pigeon with an inclination to overindulge has been crowned New Zealand’s Bird of the Year in an annual competition that has involved passionate social media battles, voting scandals and the use of Tinder.

The success of the kereru or wood pigeon was brought home by a campaign focused on the bird’s size and appetite, kicking off a meme war over which native bird is the roundest, conservation organization Forest and Bird said in a statement on Monday.

The portly endemic birds like to gorge heavily on ripe fruit that can ferment in their crop and turn to alcohol. There have been reports of kereru falling out of trees because they're too drunk to perch.

While the kereru population is classed as stable overall, it is in danger of becoming locally extinct in some areas where there has not been sustained predator control, conservation organisation Forest and Bird said.

"The fate of many forests is linked to that of the kereru, as it's the only native bird big enough to swallow and disperse the large fruit of karaka, miro, tawa and taraire."

The competition, run by Forest and Bird to raise awareness of New Zealand’s unique native birds and the threats they face, was shaken by an international voting scandal when IP addresses in Australia sent through over 300 votes for the shag, and then over 1,500 for the kaki.

However, attempts to fiddle the vote were thwarted by the competition's hawk-eyed election scrutineer.

It was not the first time the competition had seen fraudulent activity.

Last year, the white-faced heron was caught up in alleged vote fixing, while in 2015 teenage twin sisters used their parents' business account to create hundreds of fake email addresses to champion the kokako.

The competition attracts tens of thousands of passionate bird lovers from school children to octogenarians who battle for their favourites using creativity, humour and some borderline tactics to get votes.

Some enthusiasts had signed up their bird to online dating to get the word out. A kaki - a black stilt of which there are only 132 adult birds left in the wild - called Shelly D has been making connections using Tinder.

This year’s competition also prompted celebrity endorsements from Stephen Fry for the clumsy kakapo, and from comedian Bill Bailey for the rare takahe.

Prime Minister Jacinda Ardern threw her support behind the black petrel, which she called “the bogan of the birds." On Monday she admitted defeat and saluted the winning kereru on Twiter.

With more than 48,000 votes this year was the competition’s most popular yet.