This is a leucistic female Ruby-throated Hummingbird, and it is cool! One can only imagine the hubbub and speculation if this thing winged by a bunch of birders.
Although a strongly leucistic animal such as this hummingbird doesn't suffer the structural disadvantages of an albino, at least to as great a degree, I still wouldn't lay odds on the longterm prospects of our snowbird. For one, it is probably much more detectable to predators, especially when in a semi-torpor at night. And I would also wonder about its ability to attract a mate, but who knows, maybe the hummer-dudes will think she is cooler than the average bird.
Anyway, Tim reports that the snowy hummer seemed to be doing just fine, although it was seemingly the target of excessive aggression from its "normal" compadres.
You can read more details about this interesting bird HERE.
Thanks to Tim for sharing his photos, and for all his avian research work.