Quick Dips

Hope for the HiHi

New Zealand's rarest honeyeater, the hihi or stitchbird, once flew freely in the forests of the North Island. Today the endangered species has only one self-sustaining population on Little Barrier Island in the Hauraki Gulf, where it is vulnerable to ship rats from passing boats, disease from foreign birds and the weather.

The only hope for the survival of the species is if the Department of Conservation can establish viable populations on offshore islands. Since the hihi recovery programme began in 1980 nine translocation attempts have been made onto Hen, Cuvier and Kapiti islands. Only the last two efforts on Kapiti have partially achieved the goal of a self-sustaining population.

The key to the Kapiti translocations is a scientific approach involving experimental transfers of birds. Massey University doctoral student Isabel Castro has been monitoring the transfers and believes the strategies and techniques learnt from the operation will improve the hihi's chances of survival.

"With the susceptibility of birds to disease, predators, and the destruction of their habitat, their relocation has taken on a new significance," Castro says.

After working with Galapagos seabirds and United States game birds, Colombian-born Castro admits searching for hihi on Kapiti is certainly different.

"I'm used to working with large birds that can fight you, so it was a change working in the forest looking for tiny birds which nest in cavities. But after the first transfer I was hooked."

The first transfer in 1991 saw 48 Little Barrier Island birds mist-netted, weighed, measured and banded before travelling 500km south. The hihi were transported in modified cardboard cat boxes and wooden crates by plane, helicopter and car, with apple halves for in-flight food.

The experimental transfer found the birds released immediately survived better and travelled more than those held in saddleback aviaries on Kapiti for two weeks. Tracking and observation over four weeks revealed there was no difference in the survival rates of paired or grouped birds.

In 1992 a further 47 birds were released after giving blood for DNA testing. Monitoring found birds released away from other hihi survived better than those released at sites where other hihi resided. However within three days the birds were seen in areas with other hihi, on the central east side of the island.

Artificial feeders were available all year round but Castro found that hihi visited the feeders only during the breeding season from September to March, even though many plants were flowering at this time of year. She believes competition with the larger dominant honeyeater, the tui and bellbird, and the lack of nectar-producing rata, pohutukawa and karo may explain the difficulties the hihi encountered.

Castro also found hihi faced competition for nesting cavities from another bird. Kakariki had started nesting earlier and by the time hihi were looking for nest sites, most had been taken by the parakeets.

Hihi on Kapiti are now using the feeder and nest boxes, and Castro hopes these management techniques will help the birds establish. She believes the behavioural plasticity of the hihi will ensure it can adapt to the new environment.

"Hihi are beautiful and showy birds, and I am particularly interested in their behaviour during the breeding season. Hihi are the only bird species reported to mate face-to-face besides mating in the more conventional male-on-female back position. They also have a very unusual breeding system with many partners."

Castro hopes the high pitched calls of the hihi will become a more common sound on the island.

"Hihi are hard to see, they are fast and uncooperative so you can spend hours in the bush and not see any birds. But we are finding more about this fascinating bird. They have become very much part of my life."

Keith Lyons is a journalist from Christchurch