Acorn Woodpecker
Acorn Woodpecker Melanerpes formicivorus
Sound (134 KB)
DESCRIPTION:
Size:
9 inches (23 cm)
Abundance:
• Common
Quick Identification:
• White eye surrounded by black
• Black surrounding bill
• White cheeks and forehead
• Red on crown
• Pale yellow throat
Identification Tips:
• 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
Adult male:
• Red cap extends back from white forehead
Adult female:
• Red cap at rear of head separated from white forehead by black area at top of head
Similar species:
• 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.
HABITAT:
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.
WORLD RANGE:
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.
