How Do Feathers Help Thermoregulation by Birds?

Feathers help birds advertise to the opposite sex, they provide camouflage from predators, and they are used in making sounds. However, an often-overlooked function of feathers is to help regulate body temperature. By using their feathers to change the airflow patterns near the surface of their skin, birds can raise and lower their skin temperature, and by extension their core body temperature. By observing how birds use their feathers, you can develop a deeper understanding of their biology.

  1. Thermal Needs

    • Birds, like other warmblooded animals, produce excess body heat when they metabolize their food. Birds must retain some of this heat for efficient physical performance, but not so much that they overheat. Different bird species use different techniques for thermoregulation, including basking in the sun, reducing the amount of exposed skin, or huddling with other birds. But all birds use their feathers to thermoregulate. Many species are adaptable and have a very wide range of acceptable temperatures. According to veterinarian Gregory Burkett, most pet birds are comfortable from 65 to 80 degrees Fahrenheit, and when necessary they can survive in temperatures as low as 40 or as high as 90.

    Feather Types

    • Several types of feathers have evolved, but a few are especially important to thermoregulation. Contour feathers are the outermost layer of feathers that give birds their shape. Contour feathers generally overlap, and they form a weatherproof outer shell. Down feathers often cover baby birds, but they're also present under the contour feathers of many adults. Because of their frayed structure, down feathers excel at capturing air pockets to help keep birds warm. Down feathers are so efficient at trapping heat that humans use them to make blankets, jackets and pillows.

    Control

    • Feathers are attached to birds in an orderly pattern, usually in straight rows down the bird̵7;s body. The attachment points are termed "pterylae," and they are connected to specialized muscles. By manipulating the muscles, a bird can control how tightly the feathers fit together or how close they lie to his body. A bird can puff out his feathers so that a thicker layer of air is trapped near his body. Alternatively, the bird can move his contour feathers to allow a cooling breeze to blow through.

    Dry Birds

    • Birds cover their outer feathers in a layer of hydrophobic oil produced by the preen gland. This oil repels moisture and keeps the feathers dry. This is important because wet feathers condense and lose their shape. When the structure of the feathers is compromised, the feathers don't align correctly and they can't capture or hold air pockets. Birds also stay warm by using their feathers like raincoats to keep rain and water off their skin. Evaporation from the skin would produce a cooling effect, but preventing water from soaking underneath the feathers helps keep birds from getting cold.