Is abundance a good indicator of habitat quality for boreal forest songbirds?

Abundance of breeding songbirds was estimated for a number of boreal forest habitats using point count surveys. A breeding index, based on breeding behavior and information from banding records, was calculated for each site, and abundance and breeding evidence were compared; Overall, there is a strong positive relationship between abundance and breeding estimates for most species; Breeding success was compared between low- and high-abundance sites for species that showed significant changes in population over three years. High-abundance habitats did not vary significantly, whereas low-abundance habitats not only varied significantly, but also had significantly fewer breeding records in low-population years. Our results suggest that low-abundance sites are sinks where reproduction is insufficient to sustain a breeding population. Management implications and recommendations are discussed.