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Acorn Woodpecker | Melanerpes formicivorus
Eikelspecht | Carpintero bellotero
The Acorn Woodpecker is the clown among woodpeckers: glossy black with a white forehead, a red crown, a pale eye and a black mask around the bill. It lives in family groups that jointly maintain one or more 'granaries' — trees or poles with thousands of self-drilled holes, each filled with an acorn. Its noisy calls, its cooperation in breeding and those storage trees make it one of the best-studied birds of the oak woodlands of the west.
Voice
The Acorn Woodpecker is one of the loudest woodpeckers of the west. The most frequently heard sound is a harsh, laughing waka-waka-waka, often given in chorus when group members greet each other with spread wings. There is also a rolling ja-cob ja-cob and a variety of grating and rattling calls. Its distinctive laugh is said to have inspired cartoonist Walter Lantz for the voice of the cartoon character Woody Woodpecker. It also drums, but draws attention mainly by its voice.
Recording: Paul Driver — CC BY-NC-SA 4.0 · Glen Ellen, Sonoma County, California, United States · xeno-canto
Identification
Glossy black above, with a white rump and in flight a white patch at the base of the primaries. The face shows black around the base of the bill, a white or creamy forehead that continues via the cheeks to the throat, and a pale, almost white eye. The breast is black, merging through black streaks into a white belly. In the male the red crown adjoins the white forehead directly; in the female a black band separates forehead and crown. Young birds have a dark eye and a less clean pattern.
Confusion species
The combination of face pattern and group behaviour makes it hard to confuse. Red-headed Woodpecker of the east has an entirely red head and large white panels in the wing. White-headed Woodpecker, found in western pine forest, is black with an entirely white head and lacks red on the crown, apart from a red nape patch in the male. Lewis's Woodpecker, which occurs in the same oak woodland, is dark greenish-black with a pink belly and a grey collar. In flight the white rump combined with the white wing patch may recall Red-headed Woodpecker.
Habitat
Oak woodland and mixed oak-pine woodland in hills and mountains, also park-like country, streamside woods, parks and leafy residential areas, as long as there are enough acorns. Areas with several oak species are best, because a failed crop of one species can then be made up by another. The group nests and roosts in cavities in dead or living limbs and reuses them year after year. Besides acorns it eats insects, often caught in the air from a lookout perch, as well as fruit, sap and oak catkins.
Where the bird is most often found, arranged by the USNVC — the vegetation classification of the United States and Canada — and CMECS for sea and coast.
Range and movements
From western Oregon through California and the south-western United States, including Arizona, New Mexico and western Texas, south through the highlands of Mexico and Central America into the Andes of Colombia. Seven subspecies are recognised. It is resident over most of its range, but in years with a failed acorn crop groups may abandon their territory and wander.
- Resident
- Breeding (summer)
- Winter
- Passage
- dark = core range, pale = thinly spread
Where and when to look
Look for the granary: an old oak, a dead trunk, a telephone pole or even a wooden barn wall full of round holes, each with an acorn in it. Wait there a while and you will see the group coming and going, moving acorns to holes that fit better and chasing off jays and squirrels. In spring you can watch several adult birds provisioning the same nest.
Conservation
The IUCN rates the species as Least Concern (LC). Partners in Flight puts the global breeding population at about 7.5 million birds, but numbers have probably declined since the nineteenth century through development and the degradation of oak woodland. It depends on old, acorn-bearing oaks and on dead trees for nest and storage holes. Competition for nest holes with the introduced European Starling and the loss of oak woodland to disease, drought and building are local risks.
Scientific name
Melanerpes formicivorus | (Swainson, 1827)
William Swainson described the species in 1827 as Picus formicivorus, from birds from Temascaltepec in Mexico; because it has since been moved to another genus, author and year stand in parentheses. Melanerpes, introduced by Swainson himself in 1832, comes from Greek melas 'black' and herpēs 'creeper'. formicivorus means 'ant-eating', from Latin formica 'ant' and vorare 'to devour', a misplaced name: ants form only a small part of its food. The species breeds cooperatively, in groups of up to fifteen birds, in which sometimes as many as eight males and four females tend a single nest together.