Cuthbert, Francesca J., and Linda R. Wires. 1999. “Caspian Tern (Hydroprogne caspia).” The Birds of North America, edited by Paul G. Rodewald. Ithaca: Cornell Lab of Ornithology. Retrieved from the Birds of North America: https://birdsna.org/Species-Account/bna/species/caster1 doi: 10.2173/bna.403