August Molt

By August, many birds have just completed the intense rigors of nesting and raising young and now undergo a complete molt. Molt is a cyclic process of feather growth. As new feathers grow in, they push the old ones out. Why molt? Because feathers wear out. Songbirds that migrate long distances need to complete this process on a tight schedule, to be ready when it's time to strike out in September. You might not even recognize this American Goldfinch in its winter plumage.

Support for BirdNote comes from American Bird Conservancy and Bringing Back the Birds, a photo book by Owen Deutsch on the importance of protecting birdscapes. Available at amazon.com.

BirdNote^®

August Molt - Now, Where Did I Put My Tail?

Written by Bob Sundstrom

This is BirdNote.

[Scarlet Tanager song]

A day of watching birds is nearly always a day of surprises. And an August day brings surprises unique to the season. You can see some songbirds in patchy, almost unrecognizable plumage, as if they were going incognito. You can see songbirds with gaps in their wings, entire feathers gone missing. And most jarring, the occasional bird with absolutely no tail.

[Hooded Warbler song]

What’s going on? [Hooded Warbler song]

Well, many birds, which by August have just finished the intense rigors of nesting and raising young, now undergo a complete molt. Molt is a cyclic process of feather growth. As new feathers begin to grow in, they push the old ones out. In the next few weeks some birds will replace all of their feathers.

[Scarlet Tanager song]

Why do birds molt? Because feathers wear out. [Scarlet Tanager song]

Songbirds like the Scarlet Tanager and Hooded Warbler [Hooded Warbler song] we’ve been hearing, birds that migrate long distances, need to complete this process on a tight schedule. They need to be ready before it’s time to strike out for Central America in September. So sometimes all the tail feathers fall out at once, leaving a bird – for a few weeks – looking rather ungainly. [Scarlet Tanager song]

Support for BirdNote comes from American Bird Conservancy and Bringing Back the Birds, a photo book by Owen Deutsch on the importance of protecting birdscapes. Available at amazon.com.

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Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Scarlet Tanager [73950] recorded by G.A. Keller and Hooded Warbler [79440] by W.L. Hershberger.

Producer: John Kessler

Executive Producer: Chris Peterson

ID# molt-02-2011-08-13 molt-02

Sources include: Steve N.G. Howell’s Molt in North American Birds, 2010