Introduction: The North American Breeding Bird Survey (BBS) is run by approximately 2,000 skilled amateur ornithologists, and is coordinated cooperatively by the U.S. Fish and Wildlife Service and the Canadian Wildlife Service. Beginning in 1966, BBS cooperators have been collecting standardized information on North American bird populations. The BBS is a roadside survey, comprised of permanent routes that are surveyed yearly. Each route is 39.4 km (24.5 miles) long and consists of 50 stops spaced 0.8 km (0.5 mile) apart. All birds heard or seen during a 3-min observation period at each stop are recorded, and the sum of the individual stops for each species is used as an index of species density on the route. In this report, we present the population changes of the 222 bird species reported on > 50 BBS routes during 1987 and 1988. Population trends for 1966-87 are presented for comparison. Owing to space constraints, trends are not reported for States, Provinces, or physiographic regions. Instead, we present maps illustrating patterns of population change for selected species, and summarize State and physiographic strata patterns of population change as the proportion of species that increased in each region. Detailed State, Provincial, and physiographic strata changes arc available to interested readers.
Additional publication details
Federal Government Series
North American Breeding Bird Survey Annual Summary, 1988