On the individual species pages, under Life History, BAM presents the Partners in Flight population estimates for North America.
To date, the main attempt to estimate population sizes of North American passerines was conducted by the international coalition, Partners in Flight (PIF). Their continental monitoring plan published global population estimates for 448 native landbird species of the U.S. and Canada. The PIF method for population estimates (described here ) was based on relative abundance data from the North American Breeding Bird Survey (BBS), a large-scale avian monitoring program based on systematic point count censuses. The surveys are collected using a standard technique across much of North America: BBS routes along roadsides are surveyed annually to provide information on long-term population trends.
The Boreal Avian Modelling Project (BAM) is developing avian population estimates based on its comprehensive database, of which the BBS data form a part. Our approach will take into consideration methodological advancements described here as well as recommendations that were made to improve the PIF estimation techniques. Results will be posted as they become available.