BirdNote; Swallows Swallow

BirdNote®

Swallows Swallow

Written by Bob Sundstrom

This is BirdNote!

[Sound of firewood being stacked or chopped]

Remember the rhyme: “How much wood would a woodchuck chuck, if a woodchuck could chuck wood?”?

The woodchuck question has inspired many clever answers. But, truth be told, woodchucks – which are super-sized ground squirrels – don’t chuck wood at all.

We might better ask: “How many flies does a swallow swallow when a swallow swallows flies?”

[Sound of flies buzzing]

When Barn Swallows return north in April to nest in North America [Barn Swallow song], they bring a voracious appetite for flying insects. Roughly 99% of the swallows’ diet is flying insects. They gulp down millions of flies, mosquitoes, and agricultural pests, in the course of feeding themselves and their young. One Barn Swallow parent may fly 600 miles a day while foraging.

[Barn Swallow song]

Each time they visit the nest, the adults feed the young a compressed ball of freshly hawked bugs – and Barn Swallows may visit the nest 400 times per day!

[Barn Swallow song]

So how many flies do all those swallows swallow? Well, the world population of Barn Swallows is estimated to be 190 million. If each ate just 350 insects, that would mean 650 billion insects consumed in a day.

[Editor's correction: 66.5 billion in a day, not 665 billion]

Just imagine what it might be like without the swallows!

[No theme music but ever-increasing sound of flies and mosquitoes.]

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Audio provided by The Macaulay Library at the Cornell Lab of Ornithology, Ithaca, New York. Call of the Barn Swallow recorded by G.A. Keller. Flying insect audio by G.F. Budney.

Producer: John Kessler

Executive Producer: Chris Peterson

© 2010 Tune In to Nature.org May 2010

ID# 2008-05-23-swallow-04-KPLU swallow-04

Sources for statistics include: New Hampshire Fish and Game Dept. website, Aug. 2006