Thursday, June 22, 2017

Life on the Watershed: The Most Social of Them All

They are the most social of birds
Acorn woodpeckers live in tight clans and share stored acorns for food—as well as mates and the raising of the young in one common nest inside a tree cavity.

They’re year-round residents of the Peninsula Watershed, where the mixed oak/conifer forests provide abundant acorns as well as large trees with soft bark and dead trunks or limbs for storing them. Each acorn nut is stored in its own hole, When an acorn dries out and shrinks, the woodpecker moves it to a smaller hole—so that simply maintaining the granary is a constant activity.

Their abandoned nesting and roosting holes become homes for other native breeders: such as tree swallows (at left), along with chickadees, bluebirds and other “secondary cavity nesters." Woodpecker holes are also adopted by chipmunks, Western fence lizards, Gopher snakes, and some amphibians, 

Good places to see and hear Acorn woodpeckers are open slopes with scattered oaks and dead trunks or other bare limbs. 


  1. I wonder what the near total loss of tanoaks has had on the acorn woodpecker population since those trees were a major source for the birds throughout the tanoak range.

  2. Thank you for your response and concern. The presence of Sudden Oak Death (SOD) has indeed affected Tan oaks on the Peninsula Watershed. Though Tan oak death has continued over the years, most of our remaining Coastal live oaks are either resistant or in areas of low or non-SOD pathogenicity, and they remain healthy and viable. We also have substantial stands of California Valley Oak, which has shown little or no susceptibility to SOD. Consequently, while there has been some reduction in the acorn supply, the effect on our acorn woodpecker population fortunately appears to be minimal.