If you watch backyard birds, you will likely see some characteristic behaviors. One example is "foraging" styles — the behaviors that a bird uses to find food. Some birds, such as sparrows, are famous for their "double-scratch" behavior. The bird jumps forward and back, quite quickly...twice. In each forward jump, the bird lightly hooks leaf litter with its toes. Each return jump pulls the litter aside to expose the food underneath. Other species of birds, like robins, use their bills to simply grab leaf litter and toss it aside. Two strategies, one goal: expose and grab that food!
BirdNote®
Sparrows Kick, Robins Pick
Written by Bob Sundstrom
This is BirdNote.
[Song Sparrow Song; http://macaulaylibrary.org/audio/191231, 0.08-.11]
Sparrows kick.
[American Robin call]
Robins pick. Backyard birds with different, highly evolved strategies for finding food.
Watch a Song Sparrow as it forages on the leaf-covered ground. With feet held firmly side by side, it hops forward. Just as it lands, it quickly scratches backwards, over-turning leaves or soil. It often does this twice in rapid succession, in a behavior so distinctive of sparrows that it has a special name: the “double scratch.” [Sounds of rhythmic scratching in leaves] With eyes and beak trained on the ground, the sparrow's ready to snatch up any newly exposed insects or grubs or seeds.
A robin forages nearby, also atop the leaf litter. It’s clearly not in on the sparrow's game, though. It doesn’t double-scratch, or even single-scratch. Instead, it methodically picks up or brushes aside leaf after leaf with its bill, in search of prey.
Quite a few kinds of sparrows double-scratch, so it seems to be a mark of specialists in ground-feeding, often amid dense cover. Robins sometimes forage in the leaf litter, but they also seek out open, grassy areas, to pluck up worms, or fly up into trees in search of fruit.
So thanks to evolutionary variation, the sparrows kick, robins pick.
###
Bird sounds provided by The Macaulay Library at the Cornell Lab of Ornithology, Ithaca, New York. Recorded by W.L. Hershberger.
BirdNote's theme music was composed and played by Nancy Rumbel and John Kessler.
Producer: John Kessler
Executive Producer: Dominic Black
© 2016 Tune In to Nature.org January 2015/2018/2021 Narrator: Michael Stein
ID# foraging-01-2015-01-21 foraging-01
Sights & Sounds
Related Field Notes
