Here’s an interesting article from a few years aback about Joan Day-Martin, a hummingbird educator and bander. She is one of 150 people world wide certified by the US department of fish and wildlife to band hummingbirds, thus allowing them to be tracked by scientists all over. The article is full of all kinds of hummingbird information, such as:

…the bright colors of hummingbird throats (and sometimes their caps) comes not from pigment but from a trick of light. Tiny hairs called barbules split the sunlight into beams of pure color, something like a prism or the way a soap bubble creates a rainbow. That’s why when you look at a hummingbird from one angle, its throat seems black—the actual color of the feathers—but from a different perspective it appears brilliantly blue or ruby-colored.