The Canadian Breeding Bird Census (BBC) Database contains data for 928 breeding bird plot censuses representing all known censuses of breeding birds carried out in Canada during the period 1929–1993. The 928 records in the database represent 640 unique census plots located in all provinces and territories, except Prince Edward Island. The BBC, which was replaced by the current Breeding Bird Survey, is one of the longest-running surveys of bird populations in North America, and was designed to help determine abundance and distribution patterns of bird species. An important feature of the BBC Database is the habitat data associated with each census plot. The most prevalent vegetation species in different layers (canopy, shrub and ground cover) were recorded to reflect the assumption that birds respond principally to vegetative structure.