This is a Long-billed Starthroat (Heliomaster longirostris), another out of range species that Sean has been finding on the Nicoya peninsula. What he wanted to highlight here were the gorget feathers. These are the feathers located on the throat of this hummingbird and where males typically have their most colorful plumage. In most hummingbird species males develop these feathers as they age to be used for breeding displays with females. The gorget feathers actually reflect light due to their shape and the colors are not due to keratin based pigmentation. At different angles the light reflects a different color. You can see this represented below as when the bird is observed at a side angle the feathers look black. When looked at head on as males display during courtship the feathers appear iridescent. Sean will be talking more on this and hummingbird banding research in the coming weeks.
