Listening to a Continent Sing

the companion website to the book by Donald Kroodsma


Climbing the Rockies: juniper habitat, Temple Canyon Park, Canyon City, Colorado

June 8, 8:27 a.m.

Sunrise at 5:37 a.m.

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You will know them by their wing sounds before any other clue.

But I'm curious about how rapidly birds beat their wings when they fly. So I measure:

At first there are 10 visible beats that I can see in the sonagram over 0.58 seconds, for a rate of 17 wing beats per second. That's too slow for a hummingbird!

Next are 7 major beats in 0.41 seconds, for a rate of 17. At least he's consistent. But in between each of those major beats are two minor sounds, each no doubt indicating an additional wing beat, so now I measure 3 x 7/0.41 = 51 beats/second. That's more like the rate of a flying hummingbird.

In his second major burst of wing sounds (at 0:04), when he's flying away I count 10 beats/0.23 seconds, which calculates to 43 beats/second. And in his third major burst of wing sounds (at 0:05), still flying away, there are also 10 beats/0.23 seconds, again 43 beats/second.

Fascinating: I conclude that in normal flight he beats his wings 43 times per second. But during displays, or special flights, he can beat up to 51 times/second. I don't think he would stay airborne for long at 17 beats/second, so I'm guessing that he somehow chooses, for whatever reason, to make the wing sound with his feathers every third beat then.


a single meow of a spotted towhee.


Photo by Brian L. Sullivan