Vickery, Peter D. 1996. “Grasshopper Sparrow (Ammodramus savannarum).” 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/graspa doi: 10.2173/bna.239