A woodpecker, Melanerpes formicivorous, of western and south-western North America, which is known for its habit of storing acorns in holes in trees, and the male of which has black and white plumage with a distinctive red cap.
Origin
Early 20th century.
Definition of acorn woodpecker in US English:
acorn woodpecker
noun
US
A woodpecker, Melanerpes formicivorous, of western and south-western North America, which is known for its habit of storing acorns in holes in trees, and the male of which has black and white plumage with a distinctive red cap.