Table 3. Model-averaged parameter estimates based on six general linear models relating the nest success of dabbling ducks as a function of latitude and longitude, country (Canada vs. the United States), and year in the North American Prairie Pothole Region between 1935 and 2006. SE refers to standard error, and t = estimate/SE. Parameters in which t > 1.96 have 95% confidence intervals that do not include 0.

Parameter Estimate SE t
Intercept 247.5 132.2 1.87
Latitude -0.01 0.007 -1.91
Longitude -0.01 0.003 -2.84
Country 115.7 122.0 0.95
Year -0.25 0.13 -1.88
Year*Country -0.19 0.20 -0.94
Year² 0.00007 0.00004 1.88
Year²*Country 0.00005 0.00006 0.93