chewed

I made a birdfeeder out of a plastic juice container a few weeks ago. Haven't seen very many birds come to it, but the seed was slowly diminishing. This morning it was suddenly all empty. I suspected a squirrel. When I lifted it down to refill, noticed the wire I fashioned into a loop to hang it by was a bit tangled, made me guess squirrel again. It wasn't until I brought it inside that noticed there was damage. Something had chewed the opening deeper and wider.

I can see teeth marks.

My guess again: squirrel. Why did he do that? Maybe the opening wasn't big enough for him to get his head in easy, so he enlarged it? Now I can't fill as much seed. I got the idea to make this seeing similar feeders in a documentary about birds in Central Park. Those had wire mesh around the opening- I had assumed to give the birds something else to grip to. Maybe it was to thwart squirrels. I have window screening, I don't know if a squirrel could chew through that.