Activity of American White Pelicans, Pelecanus erythrorhynchos, at a traditional foraging area in Manitoba

We studied flocking and foraging activity of American White Pelicans (Pelecanus erythrorhynchos) at Grand Rapids, Manitoba. Arriving and departing pelicans used both soaring and flap-gliding flight. Arriving birds selectively joined larger-than-average loafing or foraging groups, which may facilitate food finding. Arriving flocks often split into smaller groups which landed separately around the study area or continued to other foraging sites. It is thus unlikely that flocking functions to maintain groups from the breeding colony to foraging sites. Departures to the breeding colony originated mainly among birds on loafing bars, and were strongly clumped. Birds leaving the foraging area behaved similarly to pelicans departing a colony en route to a foraging site, which argues against colonies serving as information centers. The behavior of pelicans moving between foraging sites distinguished them from arriving and departing commuters. Maximum foraging activity occurred at night, correlating with activity of some prey fish, and permitting travel during the day when thermals and formation flocking can be used to reduce flight costs.