Evaluation of repeated removal of mammalian predators on waterfowl nest success and density

Abstract

Low levels of nest success in the prairie pothole region are mainly attributed to changes in predator community and abundance. Removal of predators from large sites (≥ 4144 ha) has been an effective strategy for increasing nest success; however, trapping small sites (< 301 ha) is considered ineffective. I examined the effects of removing predators from 10, 259 ha sites in northeastern North Dakota during 2001-2002. Overall nest success for both years was greater on trapped sites (53.4%) than non-trapped sites (28.7%). Furthermore, daily survival rate was greater on removal sites, and was positively correlated with total predators removed. Differences in nest density were apparent between treatments with an increased nest density on trapped sites, however year had no effect. Pair densities did not differ between treatments, but a 2-fold increase for both trapped and non-trapped sites was found in spring 2002. Cost to produce one fledged duckling, combining all species ranged from $16-20. Overall, the results of this study indicate that repeated removal of predators on small sites is an effective strategy for increasing waterfowl production; however, feasibility will ultimately depend on the user group, budget limitations, landowner objectives, and public acceptance.