Birds could not fly without feathers. The thick coat of feathers streamlines the body and helps the bird glide smoothly through the air, and also helps keep the body warm.

The large primary, or wingtip feathers, are attached to the bones that correspond to our hands. The secondary feathers are connected to the bones that correspond to our forearms.

Types of Feathers

Feathers come in an almost infinite variety, but they fall into four main categories. Most numerous are the contour feathers which coat the body, giving it a streamlined shape. A house sparrow wears about 3,500 of these in winter, and they are so efficient at sealing in heat that it can maintain a normal temperature of 106.7° F. without difficulty in below-freezing cold. Lying benath the contour feathers are the soft down feathers, also used for insulation. Scattered among both types are the hairlike filoplumes which sometimes protrue from the coat and may serve as a kind of decoration, Flight feathers are the long stiff quills found on wings and tail. Among nocturnal owls, flight feathers are equipped with mufflers in the form of comblike projections and fringes for silent attacks on unwary prey.or possible as sensory organs.

Anatomy of a Feather

A feather is formed somewhat like the leaf of a fern. In the center is a strong, stiff shaft. The web, or flat surface, has many different parts. Tiny hooklets bind these parts together so tightly that it is hard for air to pass through the feather. Birds that stay north have more feathers during the cold winter months than they have in summer. Their feathers are longer and fluffier, and they have a thicker coat of down beneath their outer feathers than do birds of warmer climates.

When fully grown, feathers have no nerves or blood supply. They stay on the bird only because they are held tightly in the skin. Birds molt, or shed their feathers, at least once a year. New feathers replace the old ones as they fall out.

The number of feathers on birds varies greatly. As many as 11,903 feathers have been counted on a mallard duck. Small birds such as sparrows and warblers have from 1,300 to 2,600 feathers.

Questions or comments about this page?