Chatham Island Black Robin (Petroica traversi) – Bird History
Also confusingly called the Chatham Island robin-flycatcher or the Chatham Island robin, the Chatham Island black robin (Petroica traversi) has enjoyed a remarkable comeback after the population sank to just five in 1980.
The New Zealand Wildlife Service developed a program which entailed removing the eggs from the robins’ nests and transferring them to the nests of the closely related Chatham Island tit. The robins continued to lay to replace the removed eggs and in this way, it was possible to increase each season’s production. The technique had already been used with other species and in this case, the tits proved to be perfect foster-parents.
A critical turning point came in 1983/84 when some birds laid three clutches and the three pairs produced a total of 22 eggs. Eleven young Chatham island black robin survived, more than doubling the population. After that, a 13-year-old female named ‘Old Blue’ was retired from the program as a mother of six and grandmother of 11.
Chatham Island Black Robin Nesting and Habitat
The few remaining black robins were confined to the tiny 1 acre (0.4 ha) Little Mangare Island and were thus very vulnerable to the natural disaster. But 19 fledglings were reared in 1985, bringing the total population to 38, the highest number at any time this century, and by the spring of 1986, the program had been so successful it was thought that only one more season of assistance with breeding would be needed.
But there followed a severe setback when storm and bird pox reduced the population to 23. However, 11 chicks were raised in the following season and the latest total was 30 birds.
Chatham and neighboring islands are inhabited New Zealand protectorates to the east of the mainland and human settlement has made many inroads into the wildlife.
Other Endangered Birds of Robin Family
Other endangered birds of robin family living there are the Chatham Island oystercatcher (Haematopus unicolor chathamensis), a race of the New Zealand sooty oystercatcher, the Chatham Island pigeon (Hemiphaga novaeseelandiae chathamensis), a race of the New Zealand pigeon, and the Chatham Island taiko (Pterodroma magenta), one of the world’s rarest seabirds.
Also called the magenta petrel, the taiko was, until recently, known only from the type specimen collected in 1867. It was rediscovered in 1978, but it still remains a mystery as its breeding locality has not yet been discovered. However, some 26 individuals have been caught, ringed and examined, including a few recaptures, and a population of 70—100 birds has been suggested.