Fig. 2. Temporal trends in nest success in the Prairie Pothole Region of (A) Canada and (B) the United States. Nest success estimates were collected from studies based at sites in Alberta, Saskatchewan, Manitoba, North Dakota, and South Dakota from 1935 to 2006. The solid lines in panels A and B indicate the model-averaged predicted values from a series of models depicting nest success as a function of latitude, longitude, country (Canada/United States), year, year as a quadratic term, and the interactions of the above. Thin horizontal lines represent the mean value of all nest success estimates for each country (0.16 in Canada, 0.25 in the United States).