Dynamics of Seabird Multispecies Feeding Flocks: Age-Related Feeding Behaviour

Abstract

AbstractMultispecies feeding flocks of seabirds were studied in Barkley Sound, British Columbia. The flocks occurred during the post-breeding dispersal of migrant adult and juvenile seabirds. A consideration of comparative foraging success indicated that juvenile seabirds were less skilled at locating and capturing prey. Juveniles did not initiate flocks, were less adept at finding food, and had lower feeding success rates. The juveniles appeared to compensate for these inadequacies by using a different foraging strategy than adults. They increased the amount of time spent feeding and appeared to be more attracted to the presence of other feeding birds. Juveniles were less able to recognize good potential feeding areas and accessible food items. Juveniles had a greater tendency to loaf on the centrally located terrestrial loafing sites, thus increasing their chances of sighting feeding flocks. Our results demonstrated how improved post-fledging survival was achieved for juvenile seabirds feeding in the flocks. Our findings support the interpretations put forth by others to explain delayed maturity, reduced clutches in younger birds and prolonged parental care, all characteristic of seabirds.