Bird Feathers: Facts & Fluff

The fact that birds are the only creatures that sport feathers intrigues many people. This fascination is tied to the power and beauty of the wing and, in turn, the wonder of bird's feathers. Besides the obvious function of bird feathers as tools of flight, feathers have many other important functions.

Functions of Bird Feathers

• Camouflage
• Protection from weather
• Identify a bird to others of the species
• Identification and to impress or locate a mate
• Bright-colored feathers on a male impress a rival
• Provide balance
• Insulate against cold
• Buoyancy for swimming
• Protect from water
• Enable a bird to fly

Keratin: Bird Plastic
Feathers are made of keratin, a protein substance like plastic. Keratin makes up the hard material of beaks, scales of feet, legs and talons, claws and after-shaft (quill part), rachis (the central shaft where the barbs are attached to the feather), as well as the interwoven sides of the feather called the vanes. Tiny barbs link the vane filaments together with barbules that lock the barbs together.

Melanin: Color
The colors in a bird's feathers are formed by melanin, a natural pigment of actual color, but some color results from the reflection and diffraction of light due to the structure of the feather. Melanin also helps strengthen the feather. As the feather wears, it loses color. These colors change according to the season and the bird's aging. Feathers are dull, streaked, mottled or faded more in the female bird to give her extra camouflage protection while she sits and tends a nest. Males are usually the brightest of the pair to ward off competitors and to attract the female.

Preening and Molting
Birds spend much of their time preening feathers, which is the straightening and cleaning of the vanes and the filaments. Old feathers come loose and molt as they begin to wear and need to be replaced. All birds shed feathers. Most molt only once a year, but some can molt twice a year (bobolinks, goldfinches, indigo bunting and scarlet tanagers), and a few species molt three or even four times a year. The ptarmigan is one of these birds.

While it is often disputed, some ornithologists claim that oil from the oil gland is spread by the bird on its feathers during preening to make them waterproof. Feathers themselves seem to be waterproof and so the bird sheds rain easily. It is known that birds need water for bathing in order to keep their feathers clean, dry, light and working correctly.

Growing New Feathers
When a new feather begins to grow through the bird's skin, the bird removes the sheath that covers it with his bill. The feather then unfurls and continues growing. It takes about two weeks for a feather to grow to its full length.

If a bird's feathers are pulled out, they will usually grow back fairly quickly. If a feather breaks off with a piece of the shaft still in place, the feather will not be replaced until the next molt.

Types of Feathers
Down Feathers: The short, soft feathers next to the bird's skin are down feathers. Down feathers have billowy, unconnected filaments. These are called semiplumes and protect the newly hatched bird from wet and cold. Ducks and geese keep an undercoating of down throughout their lives.

Powder-down Feathers: Waterfowl such as herons and bitterns have what are called powder-down feathers which form a powdery substance on some areas of the skin. The birds rub the powder over their plumage when they preen.

Contour Feathers: The most important feathers are the contour feathers, which include the body feathers, wing feathers that are pointed and have uneven vanes and tail feathers, which are the same on each side and have a rounded end.