WatchList Species Account for Canada Warbler |
the list as a Declining Yellow List Species
The Canada Warbler breeds in the northeastern
U.S. south in the mountains to Georgia and in boreal Canada.
Its preferred habitat is cool, moist forests with mixed coniferous
and deciduous trees and a thick understory. In the southern
mountains it frequents rhododendron thickets, while favoring
forested wetlands further to the north and aspen/poplar forests
in the boreal parts of its range. During migration it is found
in thick understory in parks and in thickets along streams
and forest edges. It winters in northern South America.
Though vulnerable to human disturbance
of its breeding habitat, it will tolerate at least moderate
disturbance. It is apparently sensitive to reduction of understory
by deer browse and also to forest fragmentation. It responds
positively to changes that increase the density of understory
and negatively to those that severely reduce forest canopy.
Breeding Bird Survey (BBS) results from 1966 – 2001
indicate that populations have declined at rate of 1.9% per
year throughout its breeding range, with the greatest declines
in the Northeast, where the draining of forested wetlands
and forest fragmentation have eliminated much of its breeding
habitat. Degradation of southern mountain forests through
acid rain and the spread of the woolly adelgid, which kills
Fraser Fir, have also reduced its available habitat.
Protection of forested swamps where this warbler
breeds is essential for its conservation in a large part of
its range, but since its favored breeding areas are hard to
access, it is difficult to monitor populations. The bird probably
responds favorably to habitat changes that increase forest
understory and negatively to those which reduce the understory.
A serious threat to the Canada Warbler is the reduction
of habitat on its wintering grounds in the northern Andes,
where human population pressure is increasing with an accompanying
rapid loss of habitat. More study of its wintering habitats would be beneficial to conservation of the species.