These interesting corvids (related to crows and jays) are pine specialists — pine nuts are their preferred food.
This nutcracker was eventually successful:
Clark's Nutcracker's cache pine nuts for a year-round source of food. Because of this, they affect the dispersal and distribution of pines, e.g., sometimes the pines grow in clusters as a result of a number of seeds (typically 1-30) stored at each cache site (most often underground).
When I read this, I wondered how many cached seeds are relocated and eaten and how many germinate and become new trees? I suppose the nutcrackers "win" either way, although getting a new crop of seeds via the second route will take a lot longer!
P.S. Facts above from the Birds of North America account (Tomback 1998).