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Acorn Woodpecker

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Acorn Woodpecker - Male

Acorn Woodpecker - Male

Don DeBold

Aptly named for its favorite food, the acorn woodpecker caches acorns with a vengeance, storing thousands in a single tree, fence post, wooden building or telephone pole. Equally distinctive, however, are the clown-like markings on the bird’s face, giving it a unique look among North American woodpeckers.

Common Name:

Acorn Woodpecker

Scientific Name:

Melanerpes formicivorus

Scientific Family:

Picidae

Appearance:

  • Bill: Straight, black, relatively thick base
  • Size: 9 inches long with 17-inch wingspan, short neck gives the impression of a large head
  • Colors: White, red, black, yellow, pink
  • Markings: Dimorphic species. Males have a red crown and white forehead, and the white extends down the face to connect to a white bib that may show a yellow tinge or wash near the bottom. The chin and upper throat are black, and the white eye stands out in the black face. The nape, upperparts and tail are glossy black, though the wings show a white patch in flight and the white rump is also prominent in flight. The underparts are white except for the black breast and black streaks along the flanks. Females have the same markings as males but their crown shows less red and is black next to the forehead. For both genders, the legs and feet are grayish-black.

    Juveniles are similar to adults but with darker eyes and a red-orange crown, and they may show a pink wash on the throat.

Foods:

Nuts, insects, sap, nectar, fruit, lizards, eggs (See: Granivorous)

Habitat and Migration:

These woodpeckers prefer deciduous forests with plentiful oak trees, though they are also residents in mixed oak-pine forests. They can be found year-round along the Pacific coast from Oregon to southern California, and in similar habitat in southern Arizona, southwestern New Mexico and western Texas, with small isolated populations in southern areas of Utah and Colorado. Their range extends through central Mexico and Central America to the mountains of Colombia and Venezuela.

Acorn woodpeckers can be found in lowland areas but are generally more widespread in the mountains, and while these birds do not typically migrate, they can become more nomadic if local acorn crops are poor. Rare vagrant sightings have been noted far north and east of their expected range.

Vocalizations:

These noisy woodpeckers have a loud, laugh-like or quack-like “waka-waka” or “wak-wak” call that can vary in speed and intensity. Their typical drumming is from 2-20 evenly spaced beats.

Behavior:

These are sociable woodpeckers that stay year-round in small family groups of up to 15 or more birds, often called clans, working cooperatively to gather and cache acorns in “granary trees” with up to 50,000 or more acorns stored in a single tree. One nut is stored in each predrilled hole, and as the nuts dry out over time, the woodpeckers rearrange them so the nuts fit tightly into holes to keep them safe from other birds and wildlife, and they actively defend the tree from intruders. If a suitable tree is not available, acorn woodpeckers will cache their nuts in telephone poles, wooden fences, wooden buildings or other suitable surfaces.

While nuts make up the majority of these birds’ diet, they also will use hawking to gather insects, and in flight have an undulating path.

Reproduction:

These woodpeckers are monogamous within their family group, but one male may mate with several related females. The social group works together to excavate a cavity nest 5-60 feet above the ground, with the interior lined with wood chips. Multiple females in the group may use the same nest, though not all females may be mature enough to reproduce in the same clan. When laid, the eggs are plain white, and 3-7 is typical per brood. One female may lay 1-2 broods per year.

Both parents, along with other nest helpers in the clan, incubate the eggs for 12-14 days. Both parents and their helpers care for the altricial young for 30-32 days after hatching, and the juvenile birds may remain with the family group for several years, even after reaching sexual maturity.

Attracting Acorn Woodpeckers:

These woodpeckers are easily attracted to backyards with multiple oak trees, and they will also visit suet and sunflower seed feeders. Leaving snags available to serve as granary trees can help attract acorn woodpeckers.

Because these birds will drill into many wooden surfaces to cache their nuts, backyard birders may want to take appropriate steps to stop woodpecker damage before it starts.

Conservation:

While these woodpeckers are not considered threatened or endangered, they can be susceptible to habitat loss in areas where free-range cattle are allowed to graze through oak forests, destroying seedlings that are necessary replacements for aging trees. Acorn woodpeckers are also occasional victims of nesting site loss from competition with European starlings.

Similar Birds:

  • White-Headed Woodpecker (Picoides albolarvatus)
  • Lewis’s Woodpecker (Melanerpes lewis)
  • Yellow-Fronted Woodpecker (Melanerpes flavifrons)

Photo – Acorn Woodpecker – Male © Don DeBold
Photo – Acorn Woodpecker – Female © Kathy & sam
Photo – Granary Tree © Don DeBold

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