Population Trends in Grassland, Shrubland, and Forest Birds in Eastern North America

摘要: There is growing evidence that many species of birds have declined throughout the eastern United States during past 40 years. In cases this decline involves groups share same habitat and similar ecological requirements, indicating there may be a few general underlying causes for these population changes rather than unique explanation each species. I examined declines in three important groups: forest migrants, grassland species, shrubland These relatively specialized include large proportion songbird North America.