If it were not commonplace to see feisty Blue Jays (Cyanocitta cristata) squabbling and scrapping in our parks and back yards, how exotic and beautiful they would seem. Their plumage exhibits two rich tones of blue accented by black and white spotted stripes. We may also take feathers for granted, but they are one of the most complex structures in nature. Feathers evolved earlier than once thought, as revealed by remarkable fossils of feathered dinosaurs found in China in the early 1990s.
This feather, lost by a Bluejay, is a flight (wing) feather. Built around a strong, off-center vane, it is stiffened to press against the air on a downstroke. Its color is not the result of pigment, as are brown, black, or yellow feathers, nor is it the result of iridescence, as are the feathers of a hummingbird. Instead this brilliant blue results when sunlight is scattered by tiny air pockets in the fine barbs of the feather.
Feathers perform many functions for birds (and presumably, feathered dinosaurs). In addition to lifting birds into the sky, feathers provide thermal insulation and waterproofing. Feathers’ coloration may protect a bird by visually blending it into its habitat, or help the bird stand out and communicate its presence to the opposite sex. Many birds use feathers to line their nests. Although a single feather is very light, a bird’s full plumage is two to three times heavier than its skeleton.
Feathers get worn and are replaced through molting, but the feather in this photo doesn’t look too badly worn. Perhaps its former owner lost it in a tussle with another Jay or a would-be predator. Unfortunate for the Blue Jay, but fortunate for us to see such beauty close up.