Halkin, Sylvia L., and Susan U. Linville. 1999. “Northern Cardinal (Cardinalis cardinalis).” 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/norcar doi: 10.2173/bna.440