Rasmussen, Justin Lee, Spencer G. Sealy, and Richard J. Cannings. 2008. “Northern Saw-whet Owl (Aegolius acadicus).” 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/nswowl doi: 10.2173/bna.42