Yesterday I saw what appeared to be a mostly white hummingbird at one
of the feeders the 3rd grade class at Potter Valley Elementary has
outside its windows. I went back this morning and got three fairly
long looks at what I assume is an Anna's with an all white (genuinely
WHITE) rump and shoulders with a bright speckled green band around
its middle. It's head is grayish with sort of polka dots; the gray
on its primaries is also spotted. The tail is mostly white with
black tips. No, it is not April 1st yet. If you want to take a
look, I recommend non-school hours at the east end of the parking
lot; you can't miss the line of feeders along the north side of the
building, although I think the right-hand nectar feeder is empty.
I searched Google for piebald Hummers with no hits, but some for
albino or leucistic, i.e. not quite albino. He comes at about 10-15
minute intervals and gets a pretty good drink. These may not be all
that rare, but I've never seen one. I took some shaky video.