Speaking of that....Kitt and Mel didn't send any addresses...still want jewelry?
From Hummingbird.Net:
The brilliant, iridescent colors of hummingbird plumage are caused by the refraction of incident light by the structures of certain feathers. Like any diffraction grating or prism, these structures split light into its component colors, and only certain frequencies are refracted back to the viewer. The apparent color of any particular part of a feather depends upon the distance between the microscopic ridges in its grid-like structure. The resulting colors are much more vivid and iridescent than those of birds with only pigmented feathers. Not all hummer colors are due to feather structure, however; the duller, rusty browns of Allen's and Rufous Hummingbirds are the result of pigmentation. Iridescent hummingbird colors actually result from a combination of refraction and pigmentation, since the diffraction structures themselves are made of melanin, a pigment.
So, the pretty epithet "Flying Jewels" isn't too far off.