0 the american three-toed woodpecker (picoides dorsalis) is a medium-sized woodpecker (family picidae) .
1 this woodpecker has a length of 21 cm (8.3 in), a wingspan of 38 cm (15 in), and an average weight of 55 g (1.9 oz); its maximum lifespan in the wild is 6 years .
2  it closely resembles the black-backed woodpecker , which is also three-toed .
3  until recently , it was considered to be the same species as the eurasian three-toed woodpecker , (p .
4  tridactylus) .
5  adults are black on the head , wings and rump , and white from the throat to the belly; the flanks are white with black bars .
6  the back is white with black bars and the tail is black with the white outer feathers barred with black .
7  the adult male has a yellow cap .
8 the breeding habitat is coniferous forests across western canada , alaska and the midwestern united states .
9  it has also been breeding in various spots in michigan's upper peninsula .
10 the female lays 3 to 7 but most often 4 eggs in a nest cavity in a dead conifer or sometimes a live tree or pole .
11  the pair excavates a new nest each year .
12 this bird is normally a permanent resident , but northern birds may move south and birds at high elevations may move to lower levels in winter .
13 three-toed woodpeckers forage on conifers in search of wood-boring beetle larvae or other insects .
14  they may also eat fruit and tree sap .
15 these birds often move into areas with large numbers of insect-infested trees , often following a forest fire or flooding .
16  this bird is likely to give way to the black-backed woodpecker where the two species compete for habitat .
