Birds are the only animals that have feathers, and they serve several purposes. Feathers help birds fly, they keep birds warm, they attract the attention of potential mates, and they help scare away predators.
Did you know that your cockatiel has between 5,000 and 6,000 feathers on her body? These feathers grow from follicles that are arranged in rows known as pterylae. The unfeathered patches of bare skin on your bird’s body are called apteria.
A feather is a remarkably designed creation. The base of the feather shaft, which fits into the bird’s skin, is called the quill. It is light and hollow, but remarkably tough. The upper part of the feather shaft is called the rachis. From the rachis branch the barbs and barbules (smaller barbs) that make up most ofthe feather. The barbs and barbules have small hooks on them that enable the different parts of the feather to interlock like Velcro and form the feather’s vane or web.
Feather colors are determined by combinations of pigment in the outer layer and in the interior structure of the feather. All parrot species start out in their “wild” color, which is the color their feathers are in their native surroundings. In captive situations, new and unusual colors, called mutations, can occur. In the wild, birds of a different color mutation may be more easily spotted by predators (and eaten before they have a chance to breed and pass that color along to their offspring), but in captivity they can be paired with other different colored birds to create even more mutations. These color mutations are most often seen in cockatiels, parakeets, lovebirds, Quaker parrots, ring-necked parrots, and grass parrots.
Birds have several different types of feathers on their bodies. Contour feathers are the colorful outer feathers on the body and wings. Many birds have an undercoating of down feathers that helps keep them warm. Semiplume feathers are found on a bird’s beak, nares (nostrils), and eyelids.
A bird’s flight feathers can be classified into one of two types. Primary flight feathers are the large wing feathers that push a bird forward during flight. They are also the ones that need clipping. Secondary flight feathers, found on the inner wing, help support the bird in flight. Primary and secondary flight feathers can operate independently. The bird’s tail feathers also assist in flight by acting as a brake and a rudder.
To keep their feathers in good condition, healthy birds spend a great deal of time fluffing and preening. You may see your cockatiel seeming to pick at the base of her tail on the top side. This is a normal behavior in which the bird removes oil from the preen gland and spreads it on her feathers. The oil helps prevent skin infections and waterproofs the feathers.
Sometimes pet birds will develop white lines or small holes on the large feathers of their wings and tails. These lines or holes are referred to as stress bars or stress lines, and result from the bird being under stress as the feathers were developing. If you notice stress bars on your bird’s feathers, discuss them with your avian veterinarian. Be prepared to describe to the veterinarian anything new in your pet’s routine, because parrots are creatures of habit and sometimes react negatively to changes in their surroundings, diet, or daily activities.