Looking at the photograph of the hole the birds were working, I'd guess that
it either held overwintering squirrels, or was of great interest to them.

The hole apparently shows either chewing or scratches along nearly its
entire circumference, which could indicate that squirrels were coming into
it (or leaving it) from all directions - scratching the bark surrounding the
hole as they came and went.

If only birds are using it, there are usually scratches only on the bottom
edge where their feet would gradually remove the bark with their perching
and comings and goings.

Just one opinion... Cheers... Bob


Bob Hinkle
Solon, OH

______________________________________________________________________

Ohio-birds mailing list, a service of the Ohio Ornithological Society.
Our thanks to Miami University for hosting this mailing list.
Additional discussions can be found in our forums, at www.ohiobirds.org/forum/.

You can join or leave the list, or change your options, at:
http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS
Send questions or comments about the list to: [log in to unmask]