Caryn,
That's very cool you have roosting woodpeckers. It's funny that you mention this, because several days ago I noticed a female flicker in my flicker box "excavating" (i.e. throwing out wood chips I put in) and I'm assuming she's going to use it as a roost site. (Usually I get a squirrel moving in for the winter.)

Mike Donahue
Seattle (Beacon Hill)