大象传媒

In North America oaks form huge forests and produce acorns on an astronomical scale. Woodpeckers store acorns by drilling holes with their very hard beaks. In one tree there might be 60,000 acorns stored in this way. All woodpeckers from the same family will use the same tree to store their acorns. To start with, the birds leave newly-gathered acorns in a large hole in a tree to allow them to dry off before being placed in individual holes in the tree's bark. This larder will provide food for the family throughout the year. But the birds will have to be ready to repel raiders at all times and there is a lot of maintenance to be done as the acorns shrink and have to be placed in different holes.