Forty North Island robins released into Turitea Reserve near Palmerston North

One of the 40 robins released into Turitea Reserve in April. Photo / Palmerston North City Council

Turitea Valley's newest residents are doing their best to create a population explosion, but there's no need to call the midwife.

The much-welcomed residents are 40 North Island robins (toutouwai).

They were released in to Turitea Reserve in April with the hope they will mate and re-establish a robin population in the area.

Today, July 1, the robins make their media debut with a mini-documentary, Robins Return, to be released and the latest issue of Palmy Proud telling their story.

The robins came from Bushy Park Tarapuruhi near Whanganui after an explosion in bird numbers there.

The translocation project has involved Palmerston North City Council, Rangitāne and Massey University, among others.

The documentary premiered on Tuesday to people involved in the project.

Council senior climate change adviser Adam Jarvis told the gathering the translocation process started in 2016 with the seeking of permits. Everything was ready to go in 2019 but there was concern logging work nearby might affect the robins. The move was all set for last year, then Covid-19 arrived.

Jarvis said it had taken 15-plus years to get the 4000-hectare reserve ready for the robin release with the restoration of native plants and predator trapping.

The robins were kept in cardboard cat carriers until release but unfortunately one bird died in the box about 12 hours after being caught, Jarvis said.

It had been generations since the birds went extinct locally. The North Island robin's threat classification is at risk, declining.

As the new population grows it's hoped they will venture down through Sledge Track and into the city.

Massey University postdoctoral fellow Dr Zoe Stone has been tracking the robins since their release using drone and ground surveys. She said they are doing really well.

They have started to pair up, with maybe six or seven pairs forming. They will start breeding in September. Robins are hard to sex but the project team tried for a 50-50 male-female combination, Stone said.

She has been feeding them to get them fattened up for winter.

A robin at Tutira, near Napier, eating a mealworm. Mealworms are the favourite kai of robins and were used to attract them into cage traps at Bushy Park. Photo / Paul Taylor

The batteries in their transmitters used for monitoring have died and the shirring elastic holding them on is starting to wear, so the now useless transmitters are falling off.

However, they are still wearing a band with a unique number and coloured bands so they can be identified from a distance.

Massey University ecologist Dr Liz Parlato has worked with robins for 20 years and assisted with their capture from Bushy Park. The postdoctoral fellow says robins are incredibly friendly and very inquisitive.

She says if you take children to the bush, robins will come over and seek you out. Everyone gets an up-close and personal experience.

"If you were to see a robin you would instantly fall in love with it."

When she first started working with them they were quite restricted in distribution. Her master's thesis was on one of the first robin reintroductions to the mainland.

"It was a very special process to be involved in."

Parlato's PhD examined what factors would influence the success of robin reintroduction across multiple sites.

She said the release of the robins at Turitea marks a tremendous occasion in the restoration of habitat.

Paul Horton, Rangitāne representative on the project, said the toutouwai was chosen as the first species to reintroduce to Turitea as it will help rebalance cultural and ecological processes in the valley. Toutouwai will help keep invertebrates down in the leaf litter and having the birds in their rohe gives Rangitāne a better opportunity to tell the many cultural stories about the taonga.

Horton said it was significant Bushy Park mana whenua Ngā Rauru had given Rangitāne a gift to be able to reinstate the birds.