Fig. 1. Least squares regression line trends in percentage of time spent preening and back-riding by downy young (>12-d-old) Common Loon chicks as a function of Hg concentration (ppm) in their blood. Solid circles are actual values, squares are predicted values, and the open circle in each graph is an outlying lake. Removal of the right-most point in each graph shows that the observation had some leverage and influence on the analyses, but did not significantly change the parameter estimates for both back-riding (inclusion: beta = -34.88.26, t = -4.21; exclusion: beta = -25.917.35,t = -1.49) and preening (inclusion: beta = 12.32.76, t = 4.47; exclusion: beta = 7.415.50, t = 1.35).