There is no such species as a Yellow-Headed Hummingbird that I could find, but the head of many hummingbirds, like the Ruby-Throated Hummingbird are an irridescent green, that in the right light GLOW with a yellowish sheen that makes them appear yellow.
There are hundreds of DIFFERENT species of Humminbirds in the New World so there COULD be one with a yellow head, but if there is, I couldn't find it.
Kingdoms RAGE and go to war...but the PEasants plant potatoes..
EARTH FIRST! (we'll strip-mine the OTHER planets later.)