Woodpecker hole in Red Oak

[Snap]

I just noticed a woodpecker hole in one of our large red oaks. It's about 1" across by 3" tall and perhaps 2" in and is a neat and clean rectangle shape. I don't see insects or other exploratory holes so I am assuming it was a bird starting to excavate for a nest. We had have had a couple piliated woodpeckers around from time to time but they mostly pass through, most recently fairly recently.
Can I fill the hole with something safe for the tree?

 

[wagz]

i wouldnt. if it wants to nest there it's just going to hammer another hole. i'd just monitor for now. might be looking for ants. if they're in there and it's infested it'll come back. if it's already infested with ants it's a gonner anyway. i'd just enjoy the nature show. my 2 cents...

 

[esean]

That's from a pileated woodpecker from the shape. They won't excavate any further unless the woods rotting underneath and is full of ants. Its too much work to dig out a nest hole in solid healthy wood!

 

[Bill G]

To answer your question blackjack