Allen's Hummingbird is a small and compact hummingbird. It is extensively rusty in most plumages. Immature Allen's Hummingbirds are similar to adult females, but have both less spotting on the throat and rufous on flanks. Males have an iridescent red throat and shiny green back.

References cited in Species Profile

• Clark, Christopher James and Donald E. Mitchell. 2013. Allen's Hummingbird (Selasphorus sasin), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/501
• Cornell Lab of Ornithology. 2015. Allen's Hummingbird. All About Birds. http://www.allaboutbirds.org/guide/Allens_Hummingbird/id
• National Park Service. 2015. Allen's Hummingbird. http://www.nps.gov/chis/learn/nature/allens-hummingbird.htm
• Partners in Flight. 2015. Allen's Hummingbird. http://www.partnersinflight.org/WatchListNeeds/ALHU.htm
• Rosenberg, K.V., D. Pashley, B. Andres, P. J. Blancher, G.S. Butcher, W.C. Hunter, D. Mehlman, A.O. Panjabi, M. Parr, G. Wallace, and D. Wiedenfeld. 2014. The State of the Birds 2014 Watch List. North American Bird Conservation Initiative, U.S. Committee. Washington, D.C. 4 pages.