The aerial activities of the American white pelicans (P. erythrorhynchos) were observed at 3 separate breeding colonies located at East Shoal Lake, Manitoba, Canada, in 1981-1983. The onset of flights over a colony occurred 36 .+-. 2 days before the onset of hatching in the same colony. In each year, flights were concentrated over a single colony on any given day but differed between days. Newly arriving spring migrants were significantly more likely to be attracted to the particular colony over which most of the flights were occurring at the time of their arrival. Conspicuous flights serve to attract other pelicans to a currently active colony site, and may thereby facilitate the formation of highly synchronous breeding aggregations in this species.