I frequently get asked 'what's the hummingbird with yellow on its head?' to which the answer is either, if it's coming to a hummingbird feeder but has a short bill, it's a Verdin (!) or if it looks like the other hummingbirds apart from the yellow, it's pollen. You see it on lots of hummingbirds here, but I've never seen it to that extent. Wow!
Different plants deposit pollen in different places on a hummingbird's head. This is illustrated in the Sibley Guide to Bird Life and Behavior on page 360. In that example, the plant to deposit on the throat was a fuchsia.
As for the ID, female or 'female-type' hummingbirds are genuinely difficult, and that yellow is quite off-putting when trying to look at the bird as a whole. It also obscures the real throat color.
A couple of things stand out immediately. That tail posture, holding it up like that, is pure Black-chinned, which is what I'm going for. Anna's don't typically do that. It is generally pale, has a grayish crown, looks relatively short-tailed, the bill droops slightly and there is only a little white spot behind the eye, all of which point to Black-chinned. The habitat is also more likely for Black-chinned. Anna's isn't as common in that area at that elevation.
On the other hand, the bill isn't as long as I'd expect for Black-chinned, and it looks a little stocky overall. Which leads me to my final guess - I mean answer - a recently fledged juvenile Black-chinned Hummingbird.
Newly fledged hummingbirds can show a noticeably shorter bill than the adults for a week or two. It could also explain the extreme yellow, with a lot of clumsy first attempts at feeding from fuchsias...
Anyway, that's my guess. Where's Sheri? She'll give us the real answer
