The iris regulates the amount of light entering the eye. It also gives the characteristic color. In many parrots, the iris is dark in young birds and lighter and more pigmented as they get older. In cockatoos, the iris color usually indicates gender. In males it is black or very dark brown and in females, it is reddish or burnt orange. This iris gender determination is unique to cockatoos.
Birds have ears; however, they are not as apparently visible as in mammals. A bird’s ears are located behind and below the eye. Feathers lie over the ears and there are no ear flaps as in humans. The small opening in birds is actually the beginning of the external ear canal.
Birds can discriminate sounds; however, they are less sensitive to higher and lower vocal tones as compared to humans. On the other hand, their ability to differentiate various sounds is 10 times faster than humans. For instance, before a human could identify all the notes of a canary’s song, it would have to be slowed down 10 times!
Birds have a poorly developed sense of smell. Odors quickly fade above the ground where birds fly so, a strong sense of smell was not a necessary adaptation.
Birds also have a rather poor sense of taste because they have fewer taste buds in the mouth – taste buds are found on the roof of the mouth, not on the tongue.
A bird’s skin is very thin and appears somewhat transparent. The red hue you see on feathers areas is the underlying muscle being seen through the skin. During nesting time, a bird loses its lower chest feathers. This areas thickens and develops an enriched supply of blood to provide extra warmth to the eggs.
Feathers are like hair on mammals. A budgie has approximately 3,000 feathers! The primary purpose of feathers is to insulate and help maintain proper body temperature. They are also used in courtship displays, signs of aggression, as nest material, and flight.
Feathers are arranged in rows called pterlae, as opposed to mammal hair that grows randomly. The bare areas between the rows are called apteria.
When old feathers fall out, new feathers come in to replace them. The first sign of a new feather is a thickened, pointed projection of skin. Soon, the emerging feather, wrapped in its own protective sheath appears and is called a blood feather. If one of these feathers is damaged, bleeding will occur and must be stopped. Do NOT use styptic powder, as this will damage skin. Use flour or cornstarch to stop bleeding from a blood feather. Once the new feather has fully grown in, the sheath falls off or is removed by the bird and the new fully developed feather is a dead structure.
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