Dive bouts and feeding sites of Adelie Penguins rearing chicks in an area with fast sea-ice

Diving behavior and feeding sites of 22 Adelie Penguins (Pygoscelis adeliae) foraging at small open-water leads were simultaneously measured by bird-borne small data-loggers and land-based radio tracking in an area covered with fast sea-ice. The Adelies foraged in ice cracks along the share in early and mid January and around icebergs in late January. We identified a minimum of 1.6-3.7 feeding sites per foraging trip, executing 3.2-6.2 dice bouts of 78-85 min. duration at feeding sites. Birds changed feeding sites during 9.6% of the inter-bout intervals but staved within a site for 80.7% of the intervals. Duration of inter-bout intervals did not differ between birds changing feeding sites and those staying. Surface time to dice duration ratio increased with the dive sequence for dive bouts before leaving feeding sites, though this effect was not significant for those staying. Large variation in dice depth occurred within dive bouts, while dive bouts, feeding sites and sea depth had no strong effects on dice depth, indicating that penguins foraged at variable depth in mid and surface waters under the ice.