Measurements and observations (breeding success, territorial behaviour, morphometric measurements, blood hormone level, etc) of breeding pairs and non-breeding individual South Polar skuas at Northern Rookery, Cape Bird

The presence of adult non-breeding skuas in small groups near breeding pairs suggests that populations are limited by territorial behaviour. The size and composition of the non-breeding group was monitored at the Northern Rookery at Cape Bird.

Individuals were trapped, banded and morphometric measurements and weight were taken. Daily surveys were made of the size and composition of the group and the position of all individuals was noted twice per day. Territorial behaviour and breeding success of pairs within the group was monitored throughout the season with nests visited at least once every 3 days recording data on laying chronology, cause of breeding failure, growth rates of young and reproductive success.