Grazing and Songbird Nest Survival in Southwestern Saskatchewan

Abstract

Grassland songbird populations are declining, and one reason for this might be livestock management practices in native prairies. Although cattle grazing is a common practice in native mixed-grass prairie, little research has been conducted to date to determine its impact on prairie songbird nest survival. During the summers of 2006-2007, we examined the effects of low- to moderate-intensity cattle grazing typical of the region and nest site vegetation structure on nest survival of five species of ground-nesting songbirds in native mixed-grass prairie in southwestern Saskatchewan, Canada. There was no significant effect of grazing (P>0.10) on Sprague’s pipit (Anthus spragueii), Baird’s sparrow (Ammodramus bairdii), vesper sparrow (Pooecetes gramineus), lark bunting (Calamospiza melanocorys), or chestnut-collared longspur (Calcarius ornatus) nest survival. All five species used denser vegetation than was generally available (P <0.001). Sprague’s pipit nest survival was negatively correlated with vegetation density (P=0.055) and litter depth (P=0.033), and vesper sparrow nest survival was positively correlated with increased visibility from above (P=0.056), but nest survival of the other species was independent of vegetation structure. Our results suggest that low- to moderate intensity grazing is consistent with the conservation needs of ground-nesting songbirds in mixed-grass prairies of southwestern Saskatchewan.