It looks like it came from some form of pest, but there are no obvious holes or material above it. It's between glass and a screen with no obvious openings or holes. None of my other windows have it. We did have the house re-insulated recently, but I don't think it looked like this. Any help identifying what's going on?
I'm geographically located in Northern NJ I'm the US in the suburbs.
It does look like foam to me.
Opps sorry for late reply.
Yah if its foam then something is digging it out.
Those piles look like what ants pile up outside their nest, and I have seen fire ants do this several times in the past. Hope you figure it out!