Birding Notes

Reflections on birds and other wildlife on the edge of a southern woodland

Friday, April 24, 2009

Pileated Woodpecker – Listening?

This afternoon a male Pileated Woodpecker flew into the lower part of a tall pine on the edge of the woods. After waiting for a few quiet, still minutes, he hitched up the trunk, making scratching sounds as he went, then suddenly let out a loud, startling trumpeted call. He attacked a small, thin dead stub, splitting it open, seemed to find nothing of interest there and moved further on up the trunk.

He paused, clinging to the bark and staring at the trunk, turning his head only slightly one way, then another, then staring at the trunk again. He scratched the side of his head with a foot, then rubbed one cheek against the trunk. I thought it interesting how much time he – and other Pileated Woodpeckers I’ve watched – spent apparently doing nothing. Just being there. Though I suspect he is doing something, and I just don’t know what it is. I wondered if he could be listening for the sounds of insects under the bark?

In a quick search, I did not find many references to this possibility. The Birdwatcher’s Companion to North American Birdlife (by Christopher W. Leahy, page 384) notes, “there is some evidence . . . that woodpeckers can hear grubs and other wood-inhabiting insects moving in bark and trunks.”

And I found this more specific account on a Texas Parks and Wildlife website:

“The evidence of [a woodpecker’s excellent hearing] can be seen in the following account by a forester. ‘I once saw a pileated woodpecker fly to a tough old hickory tree in which ants were using a little knothole as their entrance. The bird didn’t drill in this obvious place. Instead, it circled the trunk, gently tapping, then pausing. Finally it proceeded to whack into the very heart of the ant nest – five feet below the knothole.’

“We do not know whether the bird heard the movements of the disturbed insects or was able to distinguish subtle differences in the tapping sound caused by the ants’ hollowed-out tunnels and nest. However, we do know that something pinpointed the spot where further investigation was needed and, since the bird cannot boast x-ray vision, it is fairly safe to assume that the woodpecker’s hearing played a major role in locating the ant nest.”


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