Foraging patterns of the antarctic shag phalacrocorax bransfieldensis at harmony point, antarctica

Abstract

During the 1995 and 1996 summer seasons, the foraging patterns of the Antarctic Shag Phalacrocorax bransfieldensis were studied by direct observation at Harmony Point, Nelson Island, South Shetland Islands. During pre-laying and incubation, individuals of both sexes usually foraged once a day—females early in the morning and males when their partners returned to their nests. Due to increasing energy requirements at the nest, rearing individuals increased the daily time invested in foraging activities, displaying more—but shorter—foraging trips. The reduction in the duration of the foraging trips through the breeding season suggests that Antarctic shags budget their activities to buffer variable food abundance or energy requirements at their nests. Here, we discuss the possibility of using the foraging parameters measured in this study in ecosystem monitoring programs.