Social foraging by waterbirds in shallow coastal lagoons in Ghana

Social foraging in waterbirds in Ghanaian coastal lagoons was studied during October and November 1994. Two types of foraging were social: directionally synchronized flocks (often involving distinctive feeding methods used in unison) and dense pecking aggregations. Social flocks were typically larger and denser than non-social flocks, and primarily involved piscivorous birds, especially the longer-legged shorebirds and egrets. It is probable that the flocks concentrate fish into temporarily high densities through herding or confusing escape reactions. We suggest that these flocks, rather than simply forming in areas of existing high prey density, may actively enhance their foraging success. There may be a true social element to either the initiation or persistence of waterbird social foraging flocks in coastal Ghana.