The Allen's Hummingbird, Selasphorus sasin, is a species of hummingbird. The Allen's Hummingbird is a small bird, with mature adults reaching only 3 to 3½ inches in length. The male Allen's has a green back and forehead, with rust-colored rufous flanks, rump, and tail. The male's throat is also an iridescent orange-red. The female and immature Allen's Hummingbirds are similarly colored, but lack the iridescent throat patch, instead having a series of speckles on their throat....