Low numbers of endangered hihi and pōpokotea birds found in Whanganui's Bushy Park Tarapuruhi

Pōpokotea being banded before release into Bushy Park Tarapuruhi earlier this year. Photo / Alina Huff

After a slow breeding season for two endangered birds found in Whanganui's Bushy Park Tarapuruhi, both are in the running for this year's Bird of the Year competition.

In 2013, 44 hihi were reintroduced to Bushy Park Tarapuruhi, with 10 more in 2018.

Bushy Park Tarapuruhi manager Mandy Brooke said this year's cohort was about half the size of last year, with six females producing 13 fledglings.

A total of 37 hihi individuals were spotted and identified by bands around their ankles in a recent hihi survey, including only six females.

"This continues to be a challenge for the growth of the population - though the females appear to be nesting and breeding successfully, our total number of females remains small," Brooke said.

Birds NZ Whanganui regional representative Peter Frost suspected it was because of inbreeding.

"All of the hihi we have at Bushy Park come from Tiritiri Matangi Island, and all the birds from Tiritiri Matangi Island came from Great Barrier Island," Frost said.

"When I was working with hihi in Bushy Park, quite often we would check their nests to see if the eggs failed, and quite often we would find dead embryos."

He said this was a sign of potential inbreeding.

His other hypothesis was that the females were the dispersive sex.

"This means they tend to leave their home territory to associate themselves with other males, and perhaps don't come back due to finding other forests," Frost said.

"Males tend to hang around, and they do quite well at Bushy Park."

National hihi conservation officer Mhairi McCready recently visited Bushy Park Tarapuruhi for a week to survey hihi and pōpokotea populations.

Hihi were first reintroduced to Bushy Park Tarapuruhi in 2013. Photo / Bevan Conley

She said 16 pōpokotea and a total of seven females were identified via their bands.

"These numbers are low, but they appear to be pairing up and, hopefully, they will breed well in the season ahead," McCready said.

The recently published Annual National Hihi Report said there were 50 adult hihi and 13 fledglings at Bushy Park Tarapuruhi.

"A female from the original 2013 translocation has historically been one of the most reliable breeders but fledged only one chick this year," Brooke said.

"Luckily, the population welcomed a new female in the 2018 release, who has produced multiple clutches since then."

Both the hihi and pōpokotea are in the running for Forest and Bird's Bird of the Year 2022 competition.

Forest and Bird's Ellen Rykers said Bird of the Year was primarily an awareness-raising activity and an opportunity to celebrate New Zealand's amazing birdlife.

She said last year's Bird of the Year received more than 56,000 verified votes.

"We think that having a couple of weeks every year where we talk about birds as a nation definitely helps nature.

"People care about what they know about – so we want them to know more about our manu [winged animals]."

She said around 80 per cent of New Zealand's native birds were threatened with extinction.

"Mainly because humans keep destroying their habitat, introduced mammals like rats, stoats and cats eat them, and climate change, of course."

She said last year's winner was the Pekapeka tou roa long-tailed bat.

"And how many people now know we have a cool native bat thanks to Bird of the Year?

"The more people engage with Bird of the Year, the more they get to find about New Zealand's amazing native birds, and how we can look after them."