Despite its widespread breeding distribution covering many remote and northern areas, the Common Loon is fairly well monitored by the Breeding Bird Survey (BBS). BBS data show a strong, Canada-wide increase relative to the 1970s. This increase is reflected in the Bird Conservation Regions (BCR) spanning Ontario and Quebec (see table below), where about 70% of the population is estimated to breed (Evers et al. 2010; all BCRs for which there are reasonably reliable results are shown below). Interestingly, results from the Canadian Lakes Loon Survey, measured as the average number of young produced per pair per year (see graph below), suggest that breeding success decreased between 1992-2010. As with other long-lived species, adult population trends may have a delayed effect in reflecting declines in breeding success associated with large-scale stressors (e.g., mercury, acid rain; Weeber 1999, Tozer et al. 2013). Because of the lack of survey coverage in the north, this assessment is considered to have medium reliability. The Common Loon is currently at an acceptable level relative to its national population goal (see BBS Canada graph below).
Additional information on: British Columbia Coastal Waterbird Survey
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
Additional information on: Canadian Lakes Loon Survey
