What does a woodpecker do with its tongue while hammering away at wood?

The woodpecker's tongue is sometimes used as a spear to capture insect grubs. Other times, it's inserted into the holes it creates where it functions as a rake, removing debris.

Factors that help the woodpecker avoid concussion injuries include:
* a beak that moves into wood, without stopping suddenly
* strong neck muscles
* a tightly packed cranium that stops the brain "sloshing" around
* an unusually long tongue that wraps around the brain/skull

Woodpeckers also produce large amounts of sticky saliva that coats the tongue, enhancing their ability to capture insects.

https://www.birdwatchingdaily.com/news/science/woodpeckers-hammer-without-headaches/