REPORT ON THE CHATHAM ISLAND TAIKO AND CHATHAM ISLAND PETREL RECOVERY PROGRAMMES (1990/91) Published by: Department of Conservation

SUMMARY Two visits were made to the Chatham Islands in September 1990 and January 1991 to assist with the Chatham Island taiko and Chatham Island petrel recovery programmes. Four new CI taiko were caught and another was recaptured at the three main breeding burrows. A new CI taiko burrow was found this season. The nest chamber of burrow Tuku No. 10 was located and an adult CI taiko was found incubating a starred egg on 14 January. A downy chick was present in this burrow on 8 February. These are the first reported observations of a CI taiko egg and young chick. A survey of CI petrels in January 1991 located 13 new burrows and 30 new birds were banded. There were ten recaptures of birds caught in previous seasons. CI petrel burrows were mostly in friable soil in the Kokopu Creek catchment; burrows located in previous seasons have been in firm soil. Laying dates, morphometrics, weight changes and duration of incubation shifts are also documented. Most birds lay in early to mid-January, there is no obvious sexual dimorphism and incubation shifts last 12-13 days. Competition for burrows with broad-billed prions is likely to be the major factor threatening the status of CI petrels.