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Avian Heat Regulation in Winter

1-9-13 mallards on ice IMG_0203On a cold, winter day, why would any bird choose to sit down on ice? While feathers are excellent insulators, the legs and feet of most birds lack this protective covering. Because of this, legs and feet are a major source of heat loss for birds. Physical adaptations to this loss of heat include constricted blood vessels in a bird’s feet, as well as the proximity of arteries and veins to each other which aids the transfer of heat. Birds exhibit behavioral adaptations as well, such as ducks and gulls standing on one leg and tucking the other among breast feathers, reducing by half the amount of unfeathered limb surface area exposed. By sitting down and covering both legs, even on ice, heat loss from limbs is minimized. If you observe closely, you will see many of the ground-feeding finches such as sparrows and redpolls also occasionally drop down and cover their legs and feet with their breast feathers for a few seconds.

2 responses

  1. I also do what the sparrows do – when the house is chilly, I pull my pajamas down to cover my ankles to warm them up. Smart birds! Seriously, great post.

    January 17, 2013 at 3:30 pm

  2. Judy

    I had domestic geese at one time. Once, in sub-zero weather, they would walk two steps, drop down on their bellies on the snow, and put their feet up and inside their feathers, almost as if they had “pockets” on the sides of their bodies. I noticed the Canadian geese doing the same thing out on the frozen lake. Perhaps geese aren’t so silly after all!

    January 17, 2013 at 6:28 pm

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