I'd seen evidence of acorn woodpeckers high up in trees before, but here's an entire granary that's easily visible from the ground. It's in the Byrne Preserve in Los Altos Hills. A single tree like this can hold 50,000 acorns by the end of the fall.
These are a community effort - run by an inter-related clan with a structure resembling a 1970s utopian commune.
It's wonderful that we now encourage landowners not to remove every tree that dies in their woodlands. These woodpeckers are just one of the 80 Californian bird species that rely on dead trees for nesting, food storing, hunting, roosting, and resting. Besides - if they can't find a tree to drill, acorn woodpeckers will happily turn to fences, utility poles and even buildings to build their larders.