Roy, Charlotte L., Christine M. Herwig, William L. Hohman, and Robert T. Eberhardt. 2012. “Ring-necked Duck (Aythya collaris).” 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/rinduc doi: 10.2173/bna.329