I always find claws at our cabin and thought it was from the birds eating them in the shallows of our beach. I find bits of claws and shells in the turds of the huge mink we have running around so they eat all of it. Same with the otters that are around.
My bet is a bird of some sort, I strongly believe that the mammals listed are used to eating things as tough as these claws. whether it's a tern, gull, kingfisher or heron depends on where you are. my 0.02
