Trappings of Success: Predator Removal for Duck Nest Survival in Alberta Parklands

Abstract

Nest survival is most limited by nest predation, which often is increased by anthropogenic causes including habitat fragmentation, mesopredator release and predator subsidies. In mallards and other upland-nesting duck species in the North American prairies, the rate of nest survival is the vital rate most influential to population dynamics, with 15%–20% survival required for maintenance of stable populations. Predator removal during the nesting season has increased duck nest survival on township-sized (9324 ha) areas of agricultural ecosystems in eastern locations of the prairie pothole region (PPR). However, predator removal has not been evaluated in western parkland habitats of the PPR where three-dimensional structure of vegetation is considerably greater. During 2015–2017, we evaluated nest survival on control and predator-removal plots at two study areas in the parklands of central Alberta, Canada. In the second year of the study, we transposed predator removal to control for habitat effects. Estimates of 34-day nest survival did not significantly differ between trapped ( x ¯ = 20.9%, 95% CI = 13.2%–33.7%) and control ( x ¯ = 17.8%, 95% CI = 10.5%–30.0%) plots in any year. We do not recommend predator removal be continued in Alberta parklands due to its ineffectiveness at improving duck nest survival at the local scale.