Nisbet, Ian C., Datlaf Vaughn Weseloh, Craig E. Hebert, Mark L. Mallowry, Alan F. Poole, Julie C. Ellis, Peter Pyle, and Michael A. Patten. 2017. “Herring Gull (Larus argentatus).” 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/hergul