Oct 16 2014
Here’s a closeup of woodpecker toes from banding day at Marcy Cunkelman’s last July.
Look at the direction of the toenails and you can you tell they belong to a woodpecker. Two claws curl forward, two curl back.
Woodpeckers have zygodactyl feet that help them cling to tree trunks.
The other foot from the same red-bellied woodpecker shows his toes open — two forward, two back. Notice that the toes aren’t all the same length. The little toe is Toe #1, the hallux.
Most perching birds have three toes forward while the hallux points back: anisodactyl feet. (You might recognize these toes from yesterday’s Swainson’s thrush photo.)
Anisodactyl is the most common form but there are four other arrangements of birds’ toes. Read more and see a diagram at this blog post from 2010.
(woodpecker photos by Kate St. John. Swainson’s thrush feet are cropped from a photo on Wikimedia Commons. Click on the Swainson’s toes to see the original photo)