Acorn Woodpecker

Acorn Woodpecker
The Acorn Woodpecker is a medium-sized, black and white bird with a red crown, glossy black and white head, white eyes, and white rump and wing patches. There is usually at least one red or yellow tipped feather on the throat. The Acorn Woodpecker is highly social and usually lives year-round in social units. Group members in temperate habitats do not forage together, but tropical populations often move together. This woodpecker is extremely territorial of granaries and sap trees. It is generally sedentary, but there are some migrant populations in areas where there are large seasonal fluctuations of insects.

The main diet of the Acorn Woodpecker consists of insects, sap, oak catkins, fruit and flower nectar. Acorns are critical for winter survival. Occassionally, it eats grass seeds, lizards and bird eggs. The bird prefers, however, flying ants. When foraging, the woodpecker often sits at the tops of trees while flycatching. Most foraging, however, is performed in or near the canopy. The woodpecker rarely goes to the ground except to pick up grit and fallen acorns. Usually, acorns are removed singly from trees, but the bird may also break off a twig holding up to three acorns. Sapsucking is a communal affair and group members congregate at a set of holes that are used repeatedly for several years.

The Acorn Woodpecker stores insects in cracks or crevices and nuts in indiviually-drilled holes in graneries. A granary tree may hold as many 50,000 holes. Holes are usually drilled in dead limbs and in thick bark during the winter. Any dead or living tree with deep dry bark can used as granary. Studies have shown that these granaries are so important that they are one of the main reasons why acorn woodpeckers live in such large families, at least in California. Only a large group can collect so many acorns and also defend them against other groups.

The Acorn Woodpecker is found from northwestern Oregon, California, the American Southwest and western Mexico through the Central American highlands and into the northern Andes of Colombia. The Acorn Woodpecker prefers pine-oak woodlands where oak trees are plentiful. They are also found in riparian corridors, and in Douglas firs, redwood and tropical hardwood forests as long as oaks are available nearby. Urban parks and suburban areas that possess numerous oak trees are often also home to this woodpecker.
Acorn Woodpecker Range Map