Acorn Woodpecker

The Acorn Woodopecker, Melanerpes formicivorus is a species of woodpecker (Picidae).

A black and white woodpecker. Black chin, yellowish throat, white cheeks and forehead, red cap. Female has smaller bill than male and has less red on crown (top of the head). In flight, it shows a white rump and wing patches that are conspicuous.

Diet
The acorn woodpecker mainly feeds on acorns. However, it will also feed on almonds, walnuts, and pecans; in California, in competition for food with Lewis's Woodpeckers; during summer it eats mostly insects, often taken on the wing -- grasshoppers, ants, beetles, flies; also takes occasional fruit such as cherries, apples, figs, also green corn; a major food especially in June and July is tree sap from small holes it drills in branches of live oaks; also from the holes dug by sapsuckers.

Calls
Its most common call is waka repeated several times; or, according to Peterson (1961), whack-up, whack-up, whack or ja-cob, ja-cob.