You’d Never Guess What an Acorn Woodpecker Eats

Acorn Woodpeckers eat insects, delicious sap, oak flowers full of pollen… and yes, acorns. They stock up on these bitter but dependable nuts from coast live oaks and California black oaks, storing them in tree trunk granaries that keep them dry and safe from squirrels and the elements throughout the winter.

“They’re the only animals that I know of that store their acorns individually in holes in trees,” said biologist Walter Koenig, of the Cornell Lab of Ornithology, who has studied acorn woodpeckers for decades at the University of California’s Hastings Natural History Reservation in Carmel Valley.

Over generations, acorn woodpeckers can drill thousands of small holes into one or several trees close to each other, giving these so-called granaries the appearance of Swiss cheese.

This sets them apart from other birds that drop acorns into already-existing cavities in trees, and animals like squirrels and jays that bury acorns in the ground.

This Deep Look episode captures how these resourceful, tap-tap-tapping birds work together to stay stocked up all year long.

Follow this video with bioGraphic’s The Anomalies: The Acorn Woodpecker, From seed to sapling – Time lapse of an oak tree, and Acorn, an animation by Madeline Sharafian.

Bonus: How to Make a Squirrel Proof Bird Feeder.