Gillihan, Scott W., and Bruce E. Byers. 2001. “Evening Grosbeak (Coccothraustes vespertinus).” 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/evegro doi: 10.2173/bna.599