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All summer long, their knocking echoed overhead, rat-a-tat-tat, rat-a-tat-tat. Now as the chill winds of winter blow, you can catch those treetop percussionists at neighborhood eateries where the suet is fresh and the view is serene. (Learn winter bird feeding tips .) These birds, belonging to the Picidae family, are a diverse lot, and they can be found in many places around the world. Here are some surprising facts about woodpeckers.

1. A red-bellied woodpecker can stick out its tongue up to two inches past the tip of its beak.

2. As their name suggests, acorn woodpeckers drill holes in which they stash acorns. Scientists have found "granary trees" with up to 50,000 acorns.

3. The red-headed woodpecker's nicknames include "half-shirt," "jellycoat," "shirt-tail bird," "flag bird," and the "flying checker-board."

4. Golden-fronted woodpeckers color themselves purple in summer, staining their faces from gorging on the fruit of the prickly pear cactus.

5. The white-headed woodpecker is a tidy diner. It deftly clings on pinecones to avoid contact with sticky pinesap.

6. True to its name, the three-toed woodpecker is missing a digit. Without a fourth toe, the bird may deliver more powerful blows, but at the cost of climbing ability.

7. Native Americans used the bills of ivory-billed woodpeckers as decorations, and traded them across North America.