Table 2. Rankings of duck nest daily survival rate (DSR) models investigating effects of habitat and grazing co-variates. Habitat co-variates include grass type (GT), nest habitat (NHAB), woodland area (WOA), and wetland area (WEA); grazing co-variates are nest-site vegetation density (NVEG), nest-site vegetation height (NVH), and residual cover (RC) co-variates. Models are nonlinear mixed effects models with a binomial error distribution (n = 633 nest-fate intervals). Only models within the 95% confidence interval group of models, i.e., Σwi = 0.95, are presented (Burnham and Anderson 1998). Model† k‡ ΔAICc§ wi| DSR(NVEG*RC) 4 0.00 0.143 DSR(NVEG) 2 0.24 0.126 DSR(NVEG*RC+RC2+WOA+WEA) 7 0.32 0.122 DSR(NVEG*RC+RC2) 5 0.45 0.114 DSR(NVEG*RC+WOA+WEA) 6 0.47 0.113 DSR(NVEG+GT) 3 1.05 0.084 DSR(NVEG*RC+GT) 5 1.25 0.077 DSR(NVEG*RC+RC2+GT) 6 2.03 0.052 DSR(NVEG+NVH) 3 2.24 0.047 DSR(NVEG+NHAB) 4 3.26 0.028 DSR(NHAB) 3 4.72 0.013 DSR(WOA) 2 4.84 0.013 DSR(Null)¶ 1 5.26 0.010 DSR(WEA) 2 5.34 0.010 †Models including interaction and/or quadratic terms include all main effects. ‡Number of estimated parameters. §The difference in AICc scores between the present model and the best model (AICc= 765.37). |Normalized relative model likelihoods. ¶Intercept-only model.