Carey, Michael, Dirk E. Burhans, and Douglas A. Nelson. 2008. “Field Sparrow (Spizella pusilla).” 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/fiespa doi: 10.2173/bna.103