Spring '06 is the first time I've observed anything
like it, but a titmouse got incessantly hung up on a
screenless window on the NW side of my house.
There's a tulip poplar right outside that upstairs
window, and the bird would perch on a branch,
jump to the windowsill, gently peck on the glass
and make some kind of query, then return to the
tree. It was not "attacking" his/her(?) reflection
so much as it was attempting to "get close to"
it...very gentle peckings: tap, tap...tap, tap, tap...
squeak. tap, tap...tap, tap, tap, tap...SQUEEEEK!
... and it went on for hours every day. Broke my heart.
Lisbeth
Franklin County, VA