Birds on organic and conventional farms in Ontario: partitioning effects of habitat and practices on species composition and abundance Original Research Article

Population declines of farmland birds over recent decades in Europe, Canada and the USA have been attributed to more intensive agricultural management. We counted birds during the 1990 breeding season on 72 field sites in southern Ontario, Canada, paired between 10 organic and 10 conventional farms for local habitat to enhance our ability to detect effects of agricultural practices. Of 68 species recorded, 58 were on organic sites, 59 on conventional. Species richness and total abundance were significantly greater on organic than conventional sites based on log-linear regression. Of 43 species analyzed with log-linear regression, eight (18.6%) were significantly (P<0.05) more abundant on organic than conventional sites and four (9.3%) approached significance (0.05