Hairy woodpecker

Appearance

Adults are mainly black on the upper parts and wings, with a white or pale back and white spotting on the wings; the throat and belly vary from white to sooty brown, depending on subspecies. There is a white bar above and one below the eye. They have a black tail with white outer feathers. Adult males have a red patch or two side-by-side patches on the back of the head; juvenile males have red or rarely orange-red on the crown.

The hairy woodpecker measures from 18–26 cm in length, 33–43 cm in wingspan and 40–95 g in weight. It is virtually identical in plumage to the smaller downy woodpecker. The downy has a shorter bill relative to the size of its head, which is, other than size and voice, the best way to distinguish them in the field.

These two species are not closely related, however, and are likely to be separated in different genera. Another way to tell the two species apart is the lack of spots on its white tail feathers. Their outward similarity is a spectacular example of convergent evolution. As to the reason for this convergence, only tentative hypotheses have been advanced; in any case, because of the considerable size difference, ecological competition between the two species is slight.

Status

With an estimated population in 2003 of over nine million individuals, the hairy woodpecker is listed by the IUCN as a species of least concern in North America.

Behavior

These birds forage on trees, often turning over bark or excavating to uncover insects. They mainly eat insects, but also fruits, berries and nuts, as well as sometimes tree sap. They are a natural predator of the European corn borer, a moth that costs the US agriculture industry more than $1 billion annually in crop losses and population control. They are also known to peck at wooden window frames and wood-sided homes that may house prey.

Migration

These birds are mostly permanent residents. Birds in the extreme north may migrate further south; birds in mountainous areas may move to lower elevations.