In winter, a foraging flock might include several species of birds: chickadees, kinglets, and even a Downy Woodpecker. Many bird species eat alone, so you might wonder why these birds have chosen to dine together. Different species foraging in a group to find food enhances the success of all. One species assists the foraging of others. It's known as "commensal feeding." And more eyes and ears help protect the flock, too.
Flocking and Foraging
By Frances Wood
This is BirdNote.
[Winter flock of chickadees and kinglets]
Take a walk in a temperate woodland this month, and you might hear this chorus. [Winter flock of chickadees and kinglets and Downy Woodpecker]
A closer look and listen reveal that this foraging flock includes several species of birds: chickadees, kinglets, and even a Downy Woodpecker [Downy Woodpecker]. Many bird species eat alone, so you might wonder why these birds have chosen to dine together.
Different species flocking together to find food, called commensal feeding, mutually enhances success. One species assists the foraging of others.
For example, in chickadee and woodpecker flocks, the woodpecker pecks off bark and moss, exposing grubs for its own consumption. But the pecking also stirs up flying insects that the chickadees swoop in to snatch.
The relationship also helps the woodpecker, because the extra eyes of the chickadees are on the lookout for predators. The watchdog chickadees alert the close-focused woodpecker when there’s danger [Chickadee sounding the notes of danger]
Because these birds, foraging together, don’t seek the same foods, the result is cooperative—or commensal—rather than competitive feeding. [More flock with Downy Woodpecker]
Learn how to provide a feast for your backyard birds when you come to our website, birdnote.org. I’m Mary McCann.
Bird calls provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Black-capped chickadee recorded by R.S. Little; Golden-crowned Kinglets by G.A. Keller, Downy Woodpecker call, by W.W.H. Gunn; and mixed flock by J. Storm.
Black-capped Chickadee 5 “dee” call recorded by C. Templeton
Producer: John Kessler
Executive Producer: Chris Peterson
© 2015 Tune In to Nature.org February 2017/2020 Narrator: Mary McCann
ID# 030106commKPLU flock-02b-2010-02-11-MM