Along the Path: A Young Person’s Guide to Exploring Nature

Story and Photos By Susan Rothrock Deo

Have you looked at a feather lately? From the shiny black of a smooth crow feather to the showy colors of a peacock’s tail, they are amazing. Birds are the only living organisms with feathers, but they weren’t the first. A group of dinosaurs, the theropods, which includes Tyrannosaurus Rex, had feathers. The ancestors of modern birds arose late during the time of the dinosaurs and some call modern birds “living dinosaurs.”

Feathers are made of proteins called keratins. All vertebrates (including mammals and birds) have alpha keratins, which are relatively flexible and the basis of mammal skin, hair, and nails. Beta keratins, which are tougher, are found in the feathers, claws and scales of birds and reptiles.

Birds use their feathers for many purposes, as did the dinosaurs: camouflage, keeping warm, and advertising who they are with patterns and colors. Feathers can also help absorb or repel water. Most important, modern birds utilize what some extinct birds attained: the ability to use feathers and other adaptations to fly! Birds take good care of their feathers. They preen them with their beaks, smoothing them and spreading a little oil from a special gland near their tail to keep them soft and supple.

Feathers grow quickly, each from its own individual follicle in the bird’s skin. They grow from the tip edges in toward the center and down toward the base. Most feathers are made up of a central shaft (rachis) and two vanes, one on each side of the shaft. The vanes have separate “barbs,” like little branches. In most feathers, the barbs hook together to make a smooth outer coat. Once a feather is grown, it is no longer alive, just like our hairs, except feathers stop growing at full size. Each bird has many kinds of feathers: flight (wings and tail), contour (give the body color and shape), semiplume (keep the body warm and dry), down (trap body heat), bristle (around the eyes and/or mouth), and filoplume (attach to nerves and help a bird sense its surroundings).

Parts of a contour feather, Wikimedia Commons

Feathers come in a variety of colors and patterns—even on the same bird. Two pigments are responsible for many colors. Melanin is the most abundant (we mammals have it in our skin and hair). It creates the blacks, grays, browns, red browns, and yellow browns, like in owls and hawks, for example. Carotenoids are the second most abundant pigments. These produce the bright reds, yellows, and oranges. Unlike melanin, which the bird makes itself, carotenoids are made by plants, algae and fungi and taken in by birds in their food. (Carrots have carotenoids, for example.) A bird’s coloration may vary depending on what is present – or lacking – in its diet. Our house finch male, for example, normally has a red rump, breast, and headband, but with a slightly different diet it might be more orange or yellow.

The next time you are out and about, be on the lookout for feathers. Notice their similarities and differences; study their details with a magnifying glass. Remember to wash your hands afterwards – and remember that collecting feathers from native birds is prohibited. (A permit is required.)