Most swallow species that nest in North America eat almost nothing except flying insects. When the bugs die off in the fall, the swallows head south to winter in the tropical zones of Central and South America and the Caribbean. However, Tree Swallows can also eat small fruits. If Tree Swallows arrive in the north before the insects are out, they’ll supplement their diets with fruit, giving them a competitive advantage for limited nesting sites.
Today's show brought to you by the Bobolink Foundation.
Tree Swallows Spend the Winter
Written by Bob Sundstrom
This is BirdNote.
The first swallows of the season, arcing across the sky, are an elegant sign of spring’s arrival. A glint of sapphire blue signals Tree Swallows, typically the earliest species to arrive north.
[Tree Swallow calls]
Most swallow species that nest in North America spend their winters in the tropical zones of Central and South America and the Caribbean. That’s largely because they eat almost nothing except flying insects. When the bugs die off in the fall, the swallows head south.
Tree Swallows, however, also eat small fruits, so they can survive for longer periods than other swallow species, which depend on bugs.
[Tree Swallow calls]
If Tree Swallows migrate north to nest and arrive before the insects are out, they’ll supplement their diets with fruit, like bayberries. These berries have a waxy skin and tree swallows are one of the few species of birds that are able to digest the waxy coating.
Some populations of Tree Swallows have been able to find enough winter fruit to not even bother migrating south! And Come springtime, that gives the Tree Swallows a competitive advantage for limited nesting sites.
Welcome Tree Swallows to your yard next spring with a nestbox. Find out how to make one, at BirdNote Dot Org.
Today’s show brought to you by the Bobolink Foundation.
[Tree Swallow song]
I’m Mary McCann.
Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Recorded by ML105074801 M Garrido.
BirdNote’s theme composed and played by Nancy Rumbel and John Kessler.
Producer: John Kessler
Managing Producer: Jason Saul
Associate Producer: Ellen Blackstone
© 2019 Tune In to Nature.org January 2019 Narrator: Mary McCann
ID# TRES-05-2019-01-23 TRES-05