At project initiation, the geographic scope of BAM encompassed the boreal forest across Canada. In 2011, BAM adopted an expanded definition of the boreal region to include the boreal region of Alaska, as well as the hemiboreal area across North America as defined by Brandt .
This expanded our study region area by almost 30% to include boreal and hemiboreal portions of southern Canada and the Upper Midwest and Northeast United States. The BAM study area, extending across the continent from Alaska to Newfoundland and Labrador, now includes the entire continental North American boreal region. This area includes more than 740 million ha, of which 430 million ha are covered with forests or other wooded land.
The Brandt (2009) definition of the boreal and hemiboreal regions (based on detailed analyses of plant distributions) provides a consistent, scientifically-based delineation of this region, unconstrained by political boundaries. Including the southern hemiboreal regions helps us to understand the ecological processes that affect boreal bird populations.
The earliest records included in the avian point-count database come from surveys conducted in the 1990s. Data from historical or current bird surveys are continually being accepted into the database.