Mystery bird: Allen's hummingbird, Selasphorus sasin

Male Allen's hummingbird, Selasphorus sasin , photographed in early summer in southern California, USA. Image: Steve Duncan . [ larger view ]. Nikon D200 w/ manual Nikkor 600 f/4 on tripod w/ gimbal mount. Question: This neotropical migrant will be an incredibly challenging bird for you to identify, but I am sure most of you can narrow it down to one of two very similar species. Answer: The male Allen's hummingbird has an iridescent green back and forehead, with iridescent rust-colored rufous flanks, rump, and tail. The male's throat is also an iridescent orange-red. This species is distinguished from the male Rufous hummingbird, Selasphorus rufus , by its green back. If you thought this bird was difficult to ID, you'll be dismayed to know that immature Allen's Hummingbirds are so similar to female Rufous Hummingbirds that they are almost indistinguishable in the field! If you have bird images, video or mp3 files that you'd like to share with a large and appreciate audience, feel free to email them to me for consideration.