The Feeding Ecology and Behavior of Five Species of Herons in Southeastern New Jersey

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Abstract
Five species of herons in south-eastern New Jersey [USA] appeared to segregate with respect to their food source. Great blue herons [Ardea herodius] ate many fish that were too large for any of the other species to take. Great egrets [Casmeroidius albus] took moderate-sized fish, some of which were larger than the 3 smaller herons could handle. They also fed in deeper water, so that the small fish that they captured may not have been available to the smaller herons. Snowy egrets, little blue herons and Louisiana herons [Egretta thula, Florida caerulea, Hydranassa tricolor, respectively,] fed on fish of similar sizes. Louisiana herons and little blue herons showed some major habitat differences, but the small herons differed even more in behavior. Each fed in special ways that the others rarely used. The Snowy egret was the species most likely to aggregate in large numbers at apparently temporary food sources such as tidal pools. Snowy egrets and Louisiana herons often fed by active pursuit. Little blue herons almost never fed this way. Snowy egrets frequently foot-stirred and hunted on mudflats. Both of these methods yielded large numbers of invertebrate prey that neither Little blue nor Louisiana herons caught. Louisiana herons crouched at the edge of banks and struck nearly horizontally at prey near the water''s surface; Little blue herons swayed their heads and then struck deeply and vertically at prey near the bottom.