Table 1. Summary of model selection results for nest survival of Loggerhead Shrikes in southeastern Alberta in 1992 and 1993. Analyses were performed using program MARK and models are ranked by ascending Akaike’s Information Criterion for small samples (AICc). ΔAICc is the change in AICc between that model and the best fitting model, wi is model weight (a measure of the relative likelihood of each model) and k is the number of model parameters. Deviance is the difference in the -2*log-likelihood between that model and the saturated model. Nest age refers to the linear age model, whereas nest age2 refers to the quadratic model. Models without nest age assume constant survival across the nest cycle.

Model AICc ΔAICc wi k Deviance
S Nest age2 + Precip + Temp 451.99 0.00 0.499 5 441.97
S Nest age2 + Precip + Temp + Nest height 453.47 1.48 0.238 6 441.44
S Nest age2 + Precip + Temp + Year 453.67 1.68 0.215 6 441.64
S Nest age2 + Precip 457.27 5.29 0.036 4 449.26
S Nest age2 + Temp 459.61 7.62 0.011 4 451.59
S Nest age + Precip + Temp 465.66 13.67 0.001 4 457.65
S Nest age2 465.71 13.72 0.001 3 459.70
S Nest age + Precip + Temp + Year 467.66 15.67 0.000 5 457.64
S Precip + Temp 473.43 21.44 0.000 3 467.42
S Precip 473.66 21.67 0.000 2 469.66
S Precip + Year 474.75 22.76 0.000 3 468.74
S Precip + Temp + Year 475.15 23.16 0.000 4 467.13
S Nest age 475.65 23.66 0.000 2 471.65
S Temp 477.86 25.88 0.000 2 473.86
S Year 477.87 25.89 0.000 2 473.87
S Constant 477.90 25.91 0.000 1 475.90
S Temp + Year 478.68 26.69 0.000 3 472.67