11 rare robin chicks raised

Press, 7 March 1984, Page 4

11 rare robin chicks raised

PA Wellington A bumper breeding season for the endangered Chatham Islands black robin had virtually assured its survival, said the Undersecretary for Internal Affairs, Mr Thompson, yesterday. There were now 20 of the robins, which in 1980 were the world’s rarest birds. The saving of the species had been credited to the group’s matriarch, “Old Blue,” he said. “Old Blue” was the mother of six, and grandmother of 11 of the bird*. Mr Thompson said it

been the most successful breeding season since research and conservation efforts were started by the Wildlife Service on Little Mangere Island in the early 19705. Eleven chicks were raised this season, five of them by the robins and six by Chatham Islands tomtit foster parents. The season began in October, 1983, with nine adult robins, only three of them male. There were now 20 black robins — nine females and 11 males. Eight were on Big Mangere Island and 12 on South-East Island, both off Pitt Island in the Chat-

hams group. Mr Thompson said that the Wildlife Service was delighted with the result and was confident that the robins’ long term survival had taken a big step towards reality. “Old Blue,” for several years the only successful breeding female, is at least 13 years old, but appeared in good health. The 4ha to sha of habitat on Mangere Island was 1 approaching saturation point, but that on South-East Island offered ample scope for expansion in at least lOOha tor, many years, Mr Thompsf'. said.

The success of the season could be attributed to superior egg production and fertility of the young breeding stock; favourable mild and moist climatic conditions during spring and summer, and the development and perfection by the service of a crossfostering technique during the last three breeding seasons. The breeding performance of the three young females, which bred for the first time, was far superior to that of the older birds and that was most encouraging, Mr Thompson said. The trio laid a

of 22 eggs, all of which were fertile. Losses which occurred could be attributed to accidents — usually petrels crash-landing and destroying foster nests at night. Mr Thompson said that the new robins were vigorous and healthy without signs of genetic degeneration in spite of the species existing at a very low population for almost a century and consequently being highly inbred. Cross-fostered robins showed no signs of malimprinting and their behaviour and performance appeared normal.