Acorn Woodpecker

1/640s at f8.0, ISO:800, Canon Mark III 1Ds w/800mm, 1.4x converter


The Acorn woodpecker is a medium-sized woodpecker. The breeding habitat is forested areas with oaks in the hills of coastal California and the southwestern United States south to Colombia. This species may occur at low elevations in the north of its range, but rarely below 1000m in Central America, and it breeds up to the timberline. The breeding pair excavates a nest in a large cavity in a dead tree or a dead part of a tree. A group of adults may participate in nesting activities: Field studies have shown that breeding groups range from monogamous pairs to breeding collectives of seven males and three females, plus up to 10 non breeding helpers. Young have been found with multiple paternities. Acorn woodpeckers, as their name implies, depend heavily on acorns for food. In some parts of their range (e.g., California), the woodpeckers create granaries or "acorn trees" by drilling holes in dead trees, dead branches, telephone poles and wooden buildings. The woodpeckers then collect acorns and find a hole that is just the right size for the acorn. As acorns dry out, they are moved to smaller holes and granary maintenance requires a significant amount of the bird's time. They also feed on insects, sap, and fruit. In California, Acorn Woodpeckers breed from April to June. An Acorn Woodpecker group may consist of 1-7 male breeders that compete to mate with 1-3 females. The nest is excavated in a large tree, which may also be a granary tree. Tree cavities are created in both dead and living trees and snags and nest holes are reused for many years. Females typically lay 5 eggs that are incubated for 11 days. Male and females incubate and tend to their young. Non-breeding helpers (young from previous years) often help with incubation and other parental duties. The young leave the nest and take their first flight at approximately 30 to 32 days after hatching and return to the nest to be fed for several weeks.
Point Reyes National Seashore, CA
 
05/25/2010