Finding the burrows of Chatham Island taiko Pterodroma magentae by radio telemetry

Abstract

The Chatham Island Taiko (Magenta Petrel) Pterodroma magentae is endangered, with a population of about 50 birds. Conventional searches from 1970 to 1986 failed to find its breeding sites. Trials of radio transmitter packages attached to Grey-faced Petrels P. macroptera gouldi and to six Taiko in 1982-1986 were satisfactory. In a major effort to find burrows, Taiko were caught and radio-tracked over three months in late 1987. Twelve Taiko were caught at night with the aid of lights. Ten birds were each fitted with a transmitter; all flew out to sea after release. Birds were tracked on 16 later occasions. Two tracked birds landed 4-6 km inland in dense bush. On subsequent searches at the bearings at which the signals became stationary, five burrows were found, in two areas, 4 km apart. During a similar operation in 1988 no Taiko were caught. Despite extensive searches, these were still the only breeding areas known in late 1993.