Identify Adult Male Rufous Hummingbirds

3.5 to -4" medium sized hummingbird.  Male rufous can be entirely rufous colored or have a spackling of bright green on their back. Their gorget is an irridecent reddish orange, when the light hits right, otherwise it appears a blackish gray.  They have a white breast.  Tail feathers are short with black tips R2 is slightly notched and nearly a diagnostic mark in identifying as a Rufous hummingbird. Whitout a good view of the spread tailfeathers it is almost impossible to tell a rufous from an Allen if it is green-backed.