Bird of the Year is back next week but in a contentious decision, the two-time champion kākāpō has been barred from the ballot.

The organisers, Forest and Bird, say this year is all about the underbirds.

Competition spokesperson Ellen Rykers says a group of volunteer campaign managers took on the task of raising the profiles of their chosen bird.

A discussion was had with the long-time kākāpō campaign manager who recognises and is appreciative of the underbird theme, she says.

"You know kākāpō is an underbird in lots of ways but probably not in Bird of the Year being a two-time champ."

But there are some fabulous underbirds in the ballot, she says.

"We have the Southern New Zealand dotterel which only has 144 birds left, so even fewer than the kākāpō, we have the red knot which makes an incredible journey every year from New Zealand to Russia and we have the pīwauwau, the rock wren which is a very cute little bird that lives up in the Alpine areas."

Another change is that previously the New Zealand dotterel was listed as one bird in the competition, but this year it had been split into the northern and southern sub-species, Rykers says.

That came after a campaign manager said they really wanted to champion the Southern dotterel this year, she says.

"They lead quite different lives, so the Northern New Zealand dotterel which is the one that most people will be familiar spends most of its time sort of on the beaches or in some sort of grassy areas up around Northland, Auckland, Coromandel.

"The Southern New Zealand dotterel lives on the mountain tops of Stewart Island and then commutes every day down to the estuaries or beach to have a feed and then back up to its nest in the mountain tops."

There was also a controversial Bird of the Year winner last year it was not a bird that won but New Zealand's only native land mammal, the long-tailed bat - although the now banned kākāpō did come second.

Voting for the Bird of the Year 2022 opens on October 17 with the winners announced on October 31.

-RNZ.