Its the first time I have heard of crows eating shells, I have seen them eat small animals and other things like seeds or even dog food but never shells, I guess I dont live close to the shore but I have seen them fool my neighbor dogs to eat the food, two or three stand at the fence making noise while they then take turns into the dog food, neighbor at times have to hide the food or put it inside, I told him to buy an auto feeder but he doesnt want to spend the $50, nice pics ✌️