Скачать или смотреть American White Pelicans - Cooperative Herding Feeding

A pod of American White Pelicans doing Cooperative Herding Feeding in Sherwood Park, Alberta, Canada.

One strategy that these pelicans can use to increase their catch is cooperative feeding. In cooperative feeding behavior, groups of pelicans (usually less than 20) work together while swimming to herd small schooling fish into a dense ball or toward shallow water, where it’s difficult to escape. This behavior can start when the presence of pelicans attracts more pelicans to the area and a group forms. The pelicans then form a line or semicircle on one side of the schooling fish and begin to swim toward each other, closing in on the school. Once one pelican strikes at a fish in the dense school, the other birds immediately begin to strike, as well.

Some researchers have observed that smaller groups of pelicans (between two and six) are the most successful at catching prey using this cooperative herding behavior. The most effective group size likely depends on several factors, including prey density and whether too many birds increases the chance of a premature strike that could scare fish away. (source: ask nature.org)