Roadside surveys of boreal forest birds: how representative are they and how can we improve current sampling?

Executive Summary.—The Boreal Avian Modelling (BAM) team examined avian survey point count data collected from across the boreal forest region of Canada to quantify roadside bias in both survey coverage and survey counts by the North American Breeding Bird Survey (BBS), the most important monitoring survey for a wide suite of bird species in the boreal. We compared data from the BBS to data from off-road surveys compiled by the Boreal Avian Modelling Project (BAM) to (1) determine whether gaps in survey coverage by the BBS might be covered by off-road surveys in the region, (2) test for roadside bias in survey counts by comparing data between roadside and off-road surveys, and (3) determine whether the statistical power to detect trends was similar between roadside and off-road surveys given comparable survey effort