The acorn woodpecker, Melanerpes formicivorus, is medium sized (9 in.), clown-faced, black and white with a distinctive red crown, glossy black and white head, white eyes, and a yellow throat. They have a limited presence (winter only) in the Park, but when you hear waka, waka, waka, their most common vocalization, you can be sure they are not very far away.
Behavior and Breeding
The highly social Acorn Woodpecker is a cooperative breeder that lives in family groups of up to a dozen. Only a pair or two may actually breed, and the remainder of the group help the parents raise the young. Acorns are probably best known for their unique method of storing acorns in specialized trees called granaries, which are available to all family members. Group living and acorn storage are not however characteristics of the population in Edgewood, which appear to be a splinter group from a family group located somewhere outside the Park boundaries. Insects are their preferred food and are eaten at any time of the year when weather permits. Acorns are supplemental and are eaten, rather than stored.
In addition to the characteristics used to identify the Acorn Woodpecker, here are some fascinating facts about woodpecker behavior, anatomy, and feeding habits that are shared by all of the woodpecker species found at Edgewood.
Their most common call is a loud waka-waka-waka-waka, which is used for greeting family members, settling territorial disputes and bickering within the group. Examples of common Acorn Woodpecker sounds can be heard here.
The Birds of North America. No 194, 1995; No 166, 1995; No 555, 2000.
Cornell Lab of Ornithology. Various publications.
Fisher, C. and Morlan, J. 1996. Birds of San Francisco and the Bay Area.
By Lee Franks. This article was originally published in the Edgewood Explorer, December 2002, as part of an article about all of the woodpeckers that can be seen at Edgewood.