Not surprisingly, species richness in woodland birds reflects the regional extent of forested habitats. The largest numbers of species tend to occur in eastern North America, especially from New England across the northern Great Lakes, and also across the northern Rocky Mountains and Pacific Northwest states/provinces. The fewest woodland birds are associated with the Great Plains, Great Basin, and southwestern deserts.
Trends within this group are a mosaic of increases and declines. Increases generally prevail in eastern North America, with some local exceptions such as portions of Arkansas and Florida. No consistent geographic patterns are apparent to the trends of woodland birds in central and western North America.
Woodland birds have generally fared well, with approximately 56% of the species exhibiting increasing trend estimates during the 1966- 1994 interval. In eastern North America where increasing trends are most prevalent, woodland habitats have generally expanded and become more mature during the last half of the twentieth century despite local habitat destruction near large urban areas. Trends in habitat availability elsewhere in the continent are less certain. The trends of woodland birds are discussed in greater detail by Peterjohn and Sauer (1994).
Peterjohn, B.G., and J.R. Sauer. 1994. Population trends of
woodland birds from the North American Breeding Bird Survey.
Wildl. Soc. Bull. 22:155-164.