Geoscience Reference
In-Depth Information
Cavity-nesting species, like the hairy woodpecker (left) and boreal owl (right), are dependent upon old-growth trees.
Woodpeckers and nuthatches forage along trunks and large branches and chip away at the bark of trees in
search of food; warblers and vireos forage for insects on small branches and leaves in the forest canopy;
flycatchers and tanagers “sit and wait” for flying insects in open areas of the forest; wood thrushes, east-
ern towhees, ovenbirds, and some warblers feed on or near ground level; and hawks and vultures soar
within and over forests searching for food.
Among the species that have been affected by the loss of old, shade-tolerant hardwood forest types are
downy woodpecker, pileated woodpecker, eastern wood-pewee, white-breasted nuthatch, and black-throated
blue warbler. Similarly, the decline of old spruce-fir forest types has reduced habitat for a number of bird spe-
cies, including red crossbill, white-winged crossbill, evening grosbeak, olive-sided flycatcher, winter wren,
and kinglets, while the loss of older mixed-wood forests has had a similar impact for Swainson's thrush. The
tree cavities of older or dying trees are also important wintering sites for small mammals, such as the northern
flying squirrel.
The health of forests also depends on wildlife species. Plant pollination by hummingbirds, bats, and bees is
critical to large numbers of flowering plants, including some willows and maples. The forest floor of the mixed
forest is brightened by a host of beautiful wildflowers, including dogtooth violet, pink and yellow lady's slip-
per, and spring beauty, which are dependent on pollinators. And flowering plants in turn serve as food sources
for some twenty-one species of butterflies in the eastern deciduous forests. Fruit-eating birds and mammals are
