How Do Feathers Keep Birds Warm?

It requires thousands and thousands of feathers and a whole lot of preening.
This story is brought to you by BirdNote, a show that airs daily on public radio stations nationwide.
Imagine a Canada Goose paddling along on a cold winter day. Can you guess how many feathers cover this goose? Hundreds? Thousands?

A single Canada Goose has between 20,000 and 25,000 feathers. A smaller bird like a sparrow or wren might have 7,000 to 10,000. Those feathers are uniquely designed to help the bird fly, shed water, or display distinctive markings. A great many feathers are the short, fluffy kind—the down, which is purposed with insulating the bird from the cold.

Birds survive in sub-zero weather by fluffing their feathers, creating layers of air and feathers. Just a fraction of an inch of this insulation can keep a bird’s body temperature at 104 degrees, even in freezing weather. People learned years ago how well goose down insulates and began stuffing comforters, sleeping bags, and clothing with it. More recently, we’ve developed artificial substitutes—but geese and other birds continue to get along just fine with the original material.

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Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Calls of the Canada Goose recorded by G.B. Renyard.
Winter wind Nature SFX Essentials recorded by Gordon Hempton of
BirdNote’s theme music was composed and played by Nancy Rumbel and John Kessler.
Producer: John Kessler
Executive Producer: Chris Peterson
Writer: Frances Wood
Narrator: Michael Stein

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