The Brown Pelican (Pelecanus occidentalis) is a large-bodied seabird that nests in colonies of 10 to upwards of 5,000 pairs, on nearshore barrier islands in subtropical and tropical North American waters. It breeds between March and August, laying 2–3 eggs and raising 1–2 chicks per year. The species is facultatively migratory during nonbreeding, with some individuals remaining resident and others leaving breeding areas. Pelicans forage in near- and offshore waters and capture schooling fish by plunge-diving. This dataset summarizes proximate density values for common prey species of Brown Pelican, collected from 2013-2014 in the Northern Gulf of Mexico at 10 breeding colonies from Texas to the Florida Panhandle. We measured proximate composition and energy density of common prey species using methods as described by Anthony et al. (2000, Lipid content and energy density of forage fishes from the northern Gulf of Alaska). We extracted lipids and proteins from regurgitated purchased fish samples. We multiplied the lipid and protein contents of each sample by standard energetic values based on their relative assimilation efficiencies (lipids: 39.5 kJ/g; proteins: 17.8 kJ/g: Schmidt-Nielsen 1997, Animal Physiology: Adaptation and Environment) to obtain the overall energy density of the sample. Detailed methods may be found in the associated publication.