Old home too small for resurgent robin

By ANNE BESTON

A tiny, black former resident of the Chatham Islands has returned home after more than half a century, testimony to one of the most remarkable conservation successes in the world.

Fourteen Chatham Islands black robins have been taken from their sanctuary on Rangatira (South East) Island to a fenced, pest-controlled 40ha on nearby Pitt Island.

Local residents held a welcome ceremony for them last week.

The fact that a new home had to be found for the robins because of a burgeoning population is one of conservation's most dramatic feats.

Loss of habitat and the introduction of rats and cats wreaked havoc on the black robin (Petroica traversi) population after European settlement. By 1900 they had been wiped out everywhere in their Chathams home apart from Little Mangere Island.

They were rediscovered there in 1938, but just two or three dozen pairs survived and they continued to decline. By 1979 they faced almost certain extinction, with just five birds left.

But conservationist Don Merton, working with the now defunct Wildlife Service, carried out a dramatic experiment to save the birds. Along with intensive management, including supplementary feeding and protection of nests from seabirds and starlings, experiments began in trying to get other birds to foster eggs and chicks.

The breakthrough came in 1981, when the last breeding pair, including the female known as Old Blue, laid three clutches that were fostered to tomtit nests and three chicks survived.

Those chicks were reintroduced to Mangere Island, and with continued intense management and cross-fostering, the population slowly recovered.

It is now about 250 birds, too many for Mangere and South East Islands, so a pest-control scheme was begun on Pitt to prepare for a transfer.

The Department of Conservation hopes that one day the robins can return to their ancestral home of Little Mangere, where vegetation is slowly regenerating.

The black robin is still classed as endangered because the birds all have the same weaknesses and strengths - a result of having similar DNA because they are all descended from that last breeding pair, Old Blue and the male known as Old Yellow. One disease could wipe them out.

Black robins live between six and 13 years and grow to about 15cm high (the size of a sparrow, with longer legs).

They forage under the forest canopy and on the forest floor for weta, grubs and worms and often pair for life.

Department of Conservation



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