Rufous or Allen's hummingbird? - So. Cal. (1 Viewer)

I saw this bird in the Los Angeles area this morning. Is it possible to tell if this is an Allen's or a rufous hummingbird? I know that females are extremely difficult to distinguish, but I wasn't entirely sure if this was a male or a female. It didn't seem to have the dark throat that males of either species have, but I also thought that females of either species should have mostly green backs, but this bird doesn't seem to have much green at all. Any thoughts?

I believe this to be an immature male Rufous Hummingbird. Allen's will have green on the back, as will female Rufous. One note of caution, male Rufous can have green backs, making positive identification of an Allen's more difficult. I do not believe it works in opposite, though (rufous backed Allen's).