On islands off British Columbia, Canada, Northwestern crows (Corvus caurinus) search rocky tide pools for sea snails called whelks. After spotting a whelk, the crow picks it up in its beak, flies upward, and drops the whelk onto the rocks. If the drop is successful, the shell breaks and the crow can dine on the whelk's soft parts. If not, the crow flies up and drops the whelk again and again until the shell breaks. Using Tinbergs four basic questions, why do crows exhibit this behavior?