Acorn Woodpecker Melanerpes formicivorus
Sound (134 KB)
9 inches (23 cm)
• White eye surrounded by black
• Black surrounding bill
• White cheeks and forehead
• Red on crown
• Pale yellow throat
• Medium-sized woodpecker
• White eye
• Black head
• Black area surrounding bill is in turn surrounded by white lower face, forehead, and throat
• Black chest, nape, back, and wings
• White bases to outer primaries appear as small white crescent in flight
• White rump
• White belly and vent, with fine dark streaks on flanks
• Black tail
• Red cap extends back from white forehead
• Red cap at rear of head separated from white forehead by black area at top of head
• White-headed Woodpecker lacks white rump and has an entirely white face and crown, and a black belly. The only medium-sized woodpecker with pale eyes.
Common and very conspicuous in the west. Seen in oak woods, pine-oak woodlands where oak trees are common, parks, towns. Found in small (2-15) noisy colonies. Drills holes in "granary tree" in fall to store acorns. During summer eats mostly insects.
NESTING & FEEDING:
BREEDING: Oak and mixed oak/coniferous woodland, often in foothills. Requires acorns and storage trees. 1, rarely 2 broods. Mating system is cooperative.
DISPLAYS: Bowing and wing spreading commonly seen; some aerial displays.
NEST: Cavity nester. Usually deciduous snag, especially oak, also poles 20 to 25 feet above the ground. Lined with chips. Both sexes help with nest construction.
EGGS: White. 1.0" (25 mm).
CHICK DEVELOPMENT: Both sexes incubate. Incubation takes 11-12 days. Development is altricial (immobile, downless, eyes closed, fed). Young leave the nest after 30-32 days. Both sexes tend young.
DIET: Mostly insects; also acorns, fruit, sap, corn. In fall/winter groups hoard by studding "storage" trees, utility poles, other wooden structures with up to 50,000 acorns. Also hoard almonds/walnuts/ pecans.
CONSERVATION: Winter resident.
NOTES: Live in communal groups of up to 16, consisting of at least 2 breeding adults plus their young of previous nestings and cousins. Large clutches result of 2 females. Reproduction highly dependent on size of acorn crop. In California maintain all-year communal territories, with communal acorn stores. In Arizona, some nest as lone pairs and migrate if insufficient food is stored; some Arizona populations do not hoard. Young independent at about 2 months. Often evicted from nest cavity by starlings. Attack squirrels, jays, nuthatches, titmice, and especially Lewis' Woodpecker (which also store acorns) that raid caches.
Melanerpes formicivorus ACORN WOODPECKER. Oak woodland, mixed oak-coniferous forest. 500-3500 m. W of Cascades and Sierra Nevada from cs Washington (rarely) and wc,sw Oregon s through n,wc,sw California to mts. of n Baja California and mts. at s tip of Baja Calif.; nc,e,se Arizona, w,ec,s New Mexico, w Texas; Sierra Madre Occidental of w Mexico from ne Sonora and w Chihuahua, s in e Sinaloa, w Durango, Nayarit, w Zacatecas, Jalisco, Michoacán, Colima and c highlands to Guanajuato, México and Puebla, n in Sierra Madre Oriental in Hidalgo, San Luis Potosí to c,nw Coahuila, s Nuevo León and sw Tamaulipas; s in c,s Veracruz, n,e Oaxaca, Tabasco, Chiapas; s Guerrero to s Oaxaca; s through Guatemala, Belize, lowland pine savanna of e Honduras and ne Nicaragua, El Salvador and highlands to w Panama. Andes, 1400-3300 m of Colombia (exc. Nariņo). A communal breeder.