Nutrient Utilization and Diet Preference of American White Pelicans Consuming Either a Mono- or Multi-Species Diet

— American White Pelicans ( Pelecanus erythrorhynchos ) are reported to consume large quantities of commercial catfish in Alabama, Arkansas, Louisiana and Mississippi, negatively impacting aquaculture production. If pelicans consume a single item diet, such as catfish, nutritional deficiencies may result. Therefore, effects of monoand multi-species diets were examined to determine nutritional impacts on pelicans in addition to determining if preferences for certain fish species exist. Twelve American White Pelicans captured in northwest Mississippi were used for a seven day metabolism trial followed by a two day preference trial. In the metabolism trial, pelicans were assigned to one of three treatment diets (four birds/diet): catfish only, carp only, or both (50% catfish and 50% carp). Pelicans consuming only catfish metabolized less dry matter, organic matter and energy than those consuming only carp or both. Four pelicans were used to determine preference for carp or catfish. Pelicans ate more (P = 0.001) carp (89% of diet) and digested nutrients from carp more efficiently than they did from catfish. Pelicans can meet nutritional requirements by consuming a mono-species diet of fish; however, certain prey may be more beneficial and even preferred for consumption. Received 15 November 2010, accepted 5 April 2011.