Acorn Woodpecker, Melanerpes uropygialis

These spectacular woodpeckers, with their clown faces and their raucous "jacob-jacob!" calls, are conspicuous in trees around the Stanford campus and in the familiar oak grasslands habitat throughout California. They store acorns in communal granary trees.

This picture shows a pair of birds shortly before copulation, not in the spring mating season, but rather during the secondary hormone rush that occurs in a number of bird species when the days shorten in the Fall.