Battle for birds on bleak island

Press, 12 February 1982, Page 12

Battle for birds on bleak island

PA Wellington A man who spends months each year on a bleak island east of New Zealand fighting . to save perhaps the world’s rarest bird from extinction has expressed hope for the tiny black robin’s survival. The population of the robin — whose last known habitat is Mangere Island in the Chathams group, 800 km offshore — was 12 this summer.

The number fell to a record low of seven in 1976 but since then the wildlife officer, Don Merton, has spent most of each summer on the island nurturing the birds to increase their number by radical conservation methods. "We’ve got a fighting chance to save the bird from extinction.” He said he hoped the number would reach 20 next spring. “The next season should make or break it.”

Mr Merton, an endangered species officer for the Wildlife Service, said he now had four pairs of robins, a “surplus female” and three

chicks which were too young to be sexed. Mr Merton has used “transferred hatching” to increase the birds’ population growth, transferring the eggs to warblers’ nests, allowing the parent robins to lay a second and sometimes a third clutch.

But after one 10-day-old chick died in a warblers’ nest, Mr Merton began moving the new chicks again soon after they hatched to the nests of Chatham Island tomtits, ferrying them by dinghy Bkm to Southeast' Island.

After the birds were reared to independence by the tits, Mr Merton would ferry them back to Mangere Island to join the main population.

But while the fostering increased the species’ growth rate, Mr Merton said he feared it could cause a problem.

One female nested but did not lay this year. Mr Merton said it was only a year old and could be too young to do so, but he was worried that

the bird could have been “imprinted” by its foster parents.

This would mean it could not mate with other robins because it thought it was a tomtit, he said.

Another problem Mr Merton feared was in-breeding after 100 years of low population numbers, and he said this might lead to the robins’ extinction.

“There has been a lot of in-breeding and it is quite possible we may be beaten with genetic problems.” These genetic abnormalities could show up any time, he said, listing infertility and juvenile deaths as ways they could show themselves.

But he said all the birds looked strong and that inbreeding might have produced a strong species better equipped to survive its predicament.

Mr Merton said he would redirect the thrust of his programme next year to a second breeding line on another island, possibly Southeast Island.