Gamble, Lawrence R., and Timothy M. Bergin. 2012. “Western Kingbird (Tyrannus verticalis).” 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/weskin doi: 10.2173/bna.227