We have a silver maple with one big dead lobe. Wife has long said lets get rid of it while we can, but I said it's great woodpecker habitat. So I hear constant peeping/chirping in the tree, look up and notice a Downy (or maybe Hairy, I haven't looked close enough) Woodpecker on the tree. Lots of holes in the maple, and it's so well hidden I can't tell which one. pretty cool.
Walked out yesterday to have another look/listen and there was a hawk (I think sharp-shinned) hanging out on the same tree, flew away when I walked out. I hope he focuses his efforts on the squirrels!

Authorities state that 90% of sharp-shinned hawk diet is birds robin size and smaller including small woodpeckers. Likely that hawk has an eye on that nest.

Yeah, that's what it seemed like. I did see the little one peeking his head out the next day & a day after, so hopefully all turned out OK (& hawk didn't get the mom). I don't know how long they stay in the nest, but it seemed to be pretty good size already. All quiet now.