The food and chick feeding of blackbellied stormpetrel (Fregetta tropica) at King George Island, South Shetlands

Abstract

Food and chick feeding of the blackbellied stormpetrel were investigated at King George Island, South Shetland Islands, from December 1995 till March 1996. Seventy-five regurgitates and 174 samples from stomach flushing were analysed. Provisioning rate and meal size of the chicks were estimated by daily and three-hourly chick weighing. The mean weight of regurgitates of adult birds was 1.63 g. Fish (53.3% of occurrence) and crustaceans (50%) formed the main part of the diet. The frequencies of crustaceans in the diet were 8.3% amphipods, 21.7% euphausiids, 1.7% mysids and 18.3% unidentified crustaceans. Cephalopods represented only a small part in the diet (1.7%). Diet composition did not change throughout the season. The feeding frequencies of the chicks were 0.98 feedings per day on average. The mean meal size ranged from 9.2 to 11.0 g. Feeding and meal size data were calculated by different methods and compared with those of other petrel species.