Survival of northern pintail ducklings in grasslands and croplands: implications for fall-seeded cereals

Abstract

Species-specific management strategies have been implemented to address persistently low continental populations of several duck species, including the northern pintail (Anas acuta). In the Canadian Prairie Pothole Region (PPR), addressing threats from spring-seeded cereals on pintail productivity may provide sufficient gains to recover populations. Research on pintail duckling ecology has revealed that duckling survival may be greater in grassland-dominated landscapes than in annual cropland-dominated landscapes, possibly limiting the benefits of fall-seeded cropping practices. Winter wheat crops increase nest success and may assist nesting pintail populations through provision of nesting refuges from spring tillage operations, earlier hatch, and greater nest densities compared to traditional spring-seeded cereal crops. Yet inadequate duckling survival may reduce these benefits. Our principal objective was to examine if pintail reproductive success in winter wheat in cropland-dominated landscapes was comparable to grassland-dominated landscapes or, alternatively, if duckling survival rates in cropland-dominated landscapes offset the gains of greater nesting success in winter wheat. We captured and radio-marked 104 nesting female pintails in grasslands and croplands of southern Saskatchewan, during 2011–2012. We modeled cumulative survival to 30 days post hatch in relation to landscape composition and land cover type, specifically, the influence of nesting in fall-seeded crops. Predicted 30-day survival for ducklings hatched in perennial cover (40.8% [85% CI = 40.0–44.6%]) in grassland-dominated landscapes and winter wheat (38.2% [32.0–44.4%]) in cropland-dominated landscapes was more than double survival of ducklings hatched in spring-seeded cropland (16.9% [12.6–21.6%]) in cropland-dominated landscapes. Ducklings moving through local environments with more perennial cover and seasonal wetlands, but less wetland edge, had increased survival. The benefit of greater nest survival in winter wheat was not completely superseded by reduced duckling survival for broods raised in intensive agricultural landscapes. The retention of grassland landscapes and expansion and promotion of fall-seeded crops in cropland-dominated landscapes can benefit northern pintails across broad regions of the PPR.