Kurt Ullman wrote:

Bird feeders are way out of the way along the tree line, don't want
bird doodoo on the deck if at all possible. I put a couple of heavy
things on the top of the garbage bins which are supposed to be critter
resistant any way. The pups look to be fairly big, so it appears that
they have been hanging around there for awhile w/o us even knowing.

They are eating SOMETHING!

Perhaps you have a crawfish infestation under your porch?