Allen's Hummingbird is a close relative of the Rufous Hummingbird. This hummingbird breeds only along a narrow strip of coastal California and southern Oregon.
It is a small bird, the mature adults are only 3 to 3.5 in in length. The male has a green back and forehead, with rust-colored rufous flanks, rump, and tail.
Berylline Hummingbirds are common in the uplands of Mexico. It is a medium-sized, colorful hummingbird.
It is 8–10 cm long, and weighs 4-5 g. The adults are colored predominantly metallic olive green with a rusty gray lower belly.