First of all, get your mind(s) out of the gutter.
The 'pecker we're talking about is Melanerpes formicivorus, aka the Acorn Woodpecker, commonly seen in the oak woodlands California.
Acorn Woodpeckers are notable for drilling holes in trees (and as seen here, wooden structures) to store their 'corns for future use. These photos taken at Pinnacles National Park.
Acorn Woodpeckers are also known for their distinctive "waka waka waka" call which was supposedly the inspiration for Woody Woodpecker's famous "laugh".






