Monday, July 15, 2024

Breeding success for one of NZ’s rarest birds

With eight New Zealand fairy tern expected to leave the nest soon, it’s been the best breeding season since 2013 for one of Aotearoa New Zealand’s rarest birds.

With fewer than 40 adult birds, the conservation status of tara iti is Nationally Critical. Despite extensive management, the population has teetered on the brink of extinction since the 1970s.

The Department of Conservation (DOC) says this season has been successful because of ongoing management of the birds and their habitats, strong support from volunteers and the wider community, new intensive management techniques from Auckland Zoo, and periods of settled weather.

DOC, alongside iwi and key stakeholders, has been developing a new recovery strategy for tara iti over the past few years. This plan includes management of the vegetation, sand, and shell at site to improve the quality of tara iti habitats, and identifying and managing new sites for the birds.

The effort works alongside ongoing predator control, artificial incubation of eggs, and seasonal monitoring by DOC rangers and volunteers. The plan is informed by ongoing research into tara iti fertility, genetics, feeding, and improvements to data and field-based best practices.

Adaptive management is an important tool in the tara iti recovery programme. For example, site management designed to prevent tara iti nesting on an exposed area at Mangawhai this season resulted in fewer losses of eggs and chicks than in previous seasons.

“By deterring the tara iti from nesting in this undesirable location we’ve seen them move to more stable areas nearby which are well protected from mobile sand during storm events. Mangawhai is the most significant breeding site with six breeding pairs, and all bar one of these pairs successfully raised chicks this year,” says DOC Biodiversity Ranger, Ayla Wiles.

In addition to DOC’s work to develop and implement the recovery plan, DOC and Auckland Zoo have maintained a strong partnership, working together over the past two years to trial raising the birds at the zoo. The programme includes artificially incubating and hatching eggs, and hand-rearing chicks. Despite there being very little experience or information on these techniques for terns, one chick was successfully reared and released in the 2020–2021 season.

Building on this success and the knowledge gained from it, Auckland Zoo successfully incubated, hatched and raised tara iti chicks this year. Five chicks were transferred to the specially designed release-aviary on a beach where the birds occur naturally – two of which were successfully released, representing 20% of the successful fledglings this year. In the aviary, the birds have the opportunity to practice flying and foraging for fish before being released to join the few remaining wild terns. If these trials prove to be successful, then captive rearing may become an invaluable tool for improving numbers of tara iti in Aotearoa-New Zealand.

Once widespread around the North Island and on the eastern South Island, tara iti now nest at only four main sites, Papakānui Spit, Pākiri Beach and Waipū and Mangawhai sandspits, and occasionally at a fifth site at Te Ārai. Tara iti often make their nests on shell and sand mounds above spring high tide, which leaves them vulnerable to predators, disturbance by people, 4WD vehicles and dogs.

Since September, a dedicated team of six tara iti DOC rangers and numerous community volunteers have been busy trapping for predators, fencing off nesting sites, and preventing nesting birds from being disturbed by humans. The rangers and volunteers have now finished the intensive stage of work as most chicks have fledged.

DOC works closely with Patuharakeke, Ngāti Wai, Ngāti Whātua o Kaipara, Ngāti Manuhiri, and Te Uri O Hau, The Shorebirds Trust, The NZ Fairy Tern Charitable Trust, About Tern, Birds NZ, and the Waipū Trapping Group to help protect tara iti.

Support for the tara iti season has also been provided by the New Zealand Defence Force, Pākiri Beach Holiday Park, Tara Iti Golf Course, iwi and landowners at Pākiri, Auckland Council, Armourguard and Auckland Zoo.

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