I spoke to the woman who reported the Allen's Hummingbird. She was
basing her identification on throat color and back color. I told her
that throat color is not a useful character and that back color is not
at all reliable. Out-of-range female Allen's and Rufous Hummingbirds
are pretty much impossible to identify in the field. I believe that the
only sure way to distinguish between out-of-range male Allen's and
Rufous Hummingbirds is by a difference in the shape of some of the tail
feathers. This difference is very difficult to see in the field, even
by observers who are very experienced with these birds. The woman still
wanted to pursue this, though, so I referred her to a couple of members
of the WBRC. I haven't heard anything more.

Rachel Lawson
BirdBox System Administrator
Seattle
RachelLawson at softhome.net