mysterious grass pile

[rieferman]

so, we put up some hardware cloth in the barn to keep squirrels out. So far, so good - no more turds showing up on the upstairs floor.

But out of nowhere, I'm finding a growing pile of grass and pine needles up there. The hardware cloth is undisturbed, and still no turds. So I don't think it's a squirrel/mouse/bird etc.

Elsewhere in my yard yesterday, I noticed a wasp carrying blades of grass... Is it used to build their mud tunnels? Maybe a wasp is dropping a few pieces each time he crawls through the hardware cloth?

Any ideas what it could be?

 

[PurdueSD]

Sounds like a finch to me...

 

[kbs2244]

Take a comfortable chair, something to read and something to drink and go spend some time up there.
If you are quiet, you should be able to see what is going on.