Somewhat Mysterious Damage on Sapling Bur Oak Bark

We have one - and only one - bur oak on our 10 acres, and I've been really glad that we have at least that one. It's a fairly young, but seemingly well established, sapling planted near the draw.

Earlier this week as I was wandering the yard, I noticed that the bark looked strange. When I looked more closely, it appeared to have been eaten off in places. There was no damage near the ground, nor were there obvious toothmarks, so a bird seemed the likeliest cause, although I also wondered about a mouse-like critter.

When I took Prariewolf out to look at it today, he noticed a woodpecker flying off. (He thought it was either a hairy or a downy.) That would be consistent with the texture on the "eaten" areas of the bark.

The questions now are "Why is this bark being eaten?" and "Is it really a woodpecker doing this damage?" and "Will this kill or set back the tree this year?"

I checked - it's the only tree in the yard getting munched on in this manner.

Could be bark beetles. Could be a weird food fetish on the part of the woodpecker.

Has anyone else ever seen damage like this before? Any ideas?

Otherwise, I'll post more about it when I know more about it!

Last note: I've got better photos, but for some reason I couldn't get a portrait format photo to load without switching to landscape format tonight. Me or the new blogger? Ah, the big questions in life!