This atlas contains distribution data for more than 300 species. Each species account is accompanied by a colour photo, and a comprehensive description of Distribution and Population Status, Breeding Biology and Abundance.
The data was compiled from 1.2 million individual breeding bird records, collected in more than 150,000 hours of time in the field.
Atlas data are showing significant changes since the first atlas was conducted 20 years earlier. For example:
*Many "Carolinian" species, including Red-bellied Woodpecker, Carolina Wren, and Northern Mockingbird have expanded northward significantly.
*Quite a few "northern" species, including Merlin and Common Raven have shown significant southward range shifts.
*Some species, such as Bald Eagle and Peregrine Falcon, have responded favourably to conservation efforts and are making strong comebacks.
*Other species, however, are in serious decline, including several grassland species, such as Henslow's Sparrow and Loggerhead Shrike, as well as many "aerial foragers," including Common Nighthawk, Whip-poor-will, Chimney Swift, and most swallows.
Are these changes the result of habitat loss, climate change, pollution, or other factors? These are just some of the questions the atlas addresses.