North American Breeding Bird Survey

The surveys were conducted during the peak of the nesting season, primarily in June. Each route was 24.5 miles long, with a total of fifty stops located at 0.5 mile intervals along the route.

There were approximately 3,700 active BBS routes across the continental U.S. and Canada, of which nearly 2,900 were surveyed annually. The BBS data were used to provide a c ontinent-wide perspective on changes in bird populations. This series contains records of counts of bird species along survey routes by species and by year.