A female hairy woodpecker about to be released after banding. Notice the absence of the red patch on the back of the head.
This one clearly shows red, so it's a male. It's not typical, though, in that the red is in two patches. Normally, there would be a single bigger patch.
Hairy woodpeckers are really quite pugnacious. They know how to use those bills. Releasing these guys is always a relief--notice the bloody fingers