Census of breeding Antarctic petrels Thalassoica antarctica and physical features of the breeding colony at Svarthamaren, Dronning Maud Land, with notes on breeding snow petrels Pagodroma nivea and south polar skuas Catharacta maccormicki

Abstract

Only about a dozen breeding colonies of the Antarctic Petrel Thalassoica antarctica are known, all confined to the Antarctic continent. In 1985 one of the largest colonies, situated in Muhlig-Hofmannfjella, Dronning Maud Land, c. 200 km from the open sea and at an elevation of 1600 m a.s.l. was censused around the time of hatching. The colony size was estimated at about 207,000 breeding pairs. Three minor colonies were discovered at Jutulsessen, Gjelsvikfjella.Microclimatic measurements were made to evaluate the physical environment experienced by the breeding petrels and their chicks in the hostile Antarctic climate. The temperatures measured and energy budget made for the hillside, where the colony was located, showed that the nests of the Antarctic Petrel are placed at relatively favourable places. The northeast facing slope with the Antarctic Petrel colony absorbed large quantities of shortwave radiation during the birds’breeding season and provided suitable microclimatic conditions for breeding.