Temporal validation of an estimator for successful breeding pairs of wolves Canis lupus in the U.S. northern Rocky Mountains

Model-based predictors derived from historical data are rarely evaluated before they are used to draw inferences. We performeda temporal validation, (i.e. assessed theperformance of apredictivemodel usingdata collected from the same population after the model was developed) of a statistical predictor for the number of successful breeding pairs of wolvesCanis lupus in the northernRockyMountains (NRM).We predicted the number of successful breeding pairs, b, in Idaho,MontanaandWyomingbasedon the distribution of pack sizes observed throughmonitoring in 2006 and2007 (b̂), and compared these estimates to the minimum number of successful breeding pairs, bMIN, observed through intensivemonitoring.bMINwas consistently includedwithin the 95%confidence intervals of b̂ for all states in both years (except for Idaho in 2007), generally following the pattern b̂L (lower 95% prediction interval for b̂), b̂MIN , b̂. This evaluation of b̂ estimates for 2006 and 2007 suggest it will be a robust model-based method for predicting successful breeding pairs of NRMwolves in the future, provided influences other than those modeled in b̂ (e.g. disease outbreak, severewinter) donot have a strong effect onwolf populations.Managers canuse b̂modelswith added confidence as part of their post-delisting monitoring of wolves in NRM.