August Molt

BirdNote^®  
August Molt  
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? 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. Songbirds like the Scarlet Tanager and the Hooded Warbler we've been hearing ...

          [Hooded Warbler song] 

... 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]

For BirdNote, I'm Mary McCann.

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 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. 
© 2013 Tune In to Nature.org     August 2018 / 2022 / 2025   
Narrator: Mary McCann

ID# molt-02-2011-08-13    molt-02

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