Winkler, David W., Kelly K. Hallinger, Daniel R. Ardia, Raleigh J. Robertson, Bridget J. Stutchbury, and Robert R. Cohen. 2011. “Tree Swallow (Tachycineta bicolor).” 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/treswa doi: 10.2173/bna.11