Table 3. Estimates of the proportional contribution of white-tailed deer, beaver, and Canada goose to the diet of gray wolves (n = 10) during a captive feeding study in Forest Lake, Minnesota, USA, 2011–2012.

Type	Prey	Priors	Disc.	Sig.	Mean	SD	Bias	Variance	MSE
Estimated	Deer	NA	NA	NA	0.941	0.003	NA	NA	NA
SIMM	Deer	1,1,1	F		0.544	0.164	−0.397	0.007	0.164
SIMM	Deer	1,1,1	W		0.656	0.090	−0.285	0.008	0.089
SIMM	Deer	20, 1, 1	F	***	0.779	0.091	−0.162	0.008	0.034
SIMM	Deer	13,1,1	W	***	0.784	0.087	−0.158	0.007	0.032
Estimated	Beaver	NA	NA	NA	0.020	0.003	NA	NA	NA
SIMM	Beaver	1,1,1	F		0.215	0.094	0.195	0.009	0.047
SIMM	Beaver	1,1,1	W	***	0.124	0.078	0.104	0.006	0.017
SIMM	Beaver	20, 1, 1	F	***	0.117	0.074	0.098	0.005	0.015
SIMM	Beaver	13,1,1	W	***	0.091	0.065	0.072	0.004	0.009
Estimated	Goose	NA	NA	NA	0.039	0.002	NA	NA	NA
SIMM	Goose	1,1,1	F		0.242	0.104	0.203	0.011	0.052
SIMM	Goose	1,1,1	W	***	0.220	0.105	0.181	0.011	0.044
SIMM	Goose	20, 1, 1	F	***	0.104	0.076	0.064	0.006	0.010
SIMM	Goose	13,1,1	W	***	0.125	0.083	0.086	0.007	0.014

Proportional contributions to diet (Estimated; Mean and SD) were estimated by bootstrapping the number of each prey (and the range of possible masses from the literature) fed to each wolf. Proportional contributions (SIMM; Mean and SD) represent posterior density distributions of Bayesian stable isotope (δ¹³C and δ¹⁵N) mixing models formulated with various priors (from non-informative to minimum informative prior) and discrimination factors (i.e., red fox [F] and wolf [W]). In column Sig., *** indicates when the 95% CI of the difference between the estimated values and SIMM posteriors overlapped zero. Priors represent the vector of α values of a Dirichlet distribution corresponding to deer, beaver, and goose, respectively.