Photo courtesy Charles Martinez
This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the acorn woodpecker.
Many diverse wildlife species rely on acorns for food and acorns provide around half of the annual diet for these woodpeckers. Although they prefer to catch flying insects and will eat fruits, seeds and sap, it is stored nuts that get them through when insects are not available.
Acorn woodpeckers are medium-sized birds with a black back and black patch around the bill. Males wear a red cap which extends to a whitish forehead. In females, the red is further back on the head and a black band borders the white face.
These unusual woodpeckers live in complicated social systems of cooperative behaviors. Typically, a family group of 12 or more individuals defend a territory centered around a granary tree, which acts as a food storage area. This tree may have up to 50,000 holes drilled to hold an acorn. Each acorn is wedged tightly into a hole, making it difficult for other animals to remove.
These birds will also use human structures including fence posts, poles, buildings and wooden house siding to store nuts. If winter stores are depleted, the group must move on.
Exhibiting a behavior extremely rare among birds, acorn woodpeckers often practice joint nesting in which multiple breeding males and females share one nest. Young may stay with parents for several years and act as helpers in raising subsequent broods.
These birds live year-round in pine/oak forests along the West Coast and in parts of the southwest through Mexico and Central America. When acorns are scarce, they may wander irregularly. We are out of their normal range, but one group has been reported living in an area near Durango for several years.
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