Nine species of herons, egrets and ibises [Egretta thula, Florida caerula, Hydranassa tricolor, Eudocimus albus, Bubulcus ibis, Casmerodius albus, Nycticorax nycticorax, Plegadis falcinellus and Nyctanassa violacea] were followed by airplane from a nesting colony near Beaufort, North Carolina to their feeding sites. Except for cattle egrets, which flew exclusively to fields and dumps, the birds few mainly to saltmarsh habitat. The selection of feeding habitats by great egrets and Louisiana herons was directly related to tidal depth. The great egret was the only species that effectively used eelgrass [Zostera marina] beds, and its use of this habitat was restricted to between 1.5 h before and after low tide. Shorter-legged herons probably did not use eelgrass regularly because the water was too deep. Most great egrets, white ibises, Louisiana herons and snowy egrets used areas near the colony (< 4 km). Great egrets, black-crowned night herons and white ibises flew farther from the colony at high than at low tide. Great egrets traveled farther from the colony when they used thermals and the rate of travel to feeding sites was the same, whether or not thermals were used. Aggressive encounters were observed at the landing sites of great egrets, Louisiana herons, snowy egrets and black-crowned night herons. Cattle egrets and white ibises often flew in groups to feeding sites. Colonies may act as information centers, where unsuccessful birds follow successful ones to better feeding locations.
Additional Publication Details
Feeding habitat use by colonially breeding herons egrets and ibises in North Carolina USA