Body Mass in Common Loons (Gavia immer) Strongly Associated with Migration Distance.

The article discusses a research study which examined the association of the body mass in Common Loons, Gavia immer, with migration distance. Topics covered are the clinal variation in body mass, tarsal width and bill length in loons from populations in the upper Great Lakes and central Canada, and the resulting three migration groups based on band return and satellite tracking. Also discussed is the male and female pair differences related to migration distance.