High-intensity short-duration grazing during spring is not an effective habitat management tool for Northern Bobwhites in Colorado

Abstract

Abstract Many wildlife species, like Northern Bobwhite (Colinus virginianus), are reliant on periodic environmental disturbance to maintain heterogeneity in vegetation patterns. The Northern Bobwhite is a species of conservation concern requiring different vegetation types for nesting and brood-rearing stages, as well as for protection from predators and extreme weather. In northeastern Colorado, there are few management options to increase disturbance, other than domestic livestock grazing, to manage Northern Bobwhite habitat. As high-intensity short-duration grazing has shown promise as a mode of disturbance to manage Northern Bobwhite habitat in other regions, I used a randomized block design to test the effect of spring high-intensity short-duration grazing on Northern Bobwhites and their habitat in northeastern Colorado from 2016 to 2019. Specifically, I monitored Northern Bobwhite nest and brood survival and habitat selection in relation to grazing treatments over 3 years. I found that grazing had no effect on nest or brood survival or brood habitat selection, but Northern Bobwhites selected against grazed plots for nesting. Nest survival was negatively influenced by percent litter around the nest, and Northern Bobwhites selected nest sites with more grass cover and less bare ground. Broods selected habitat with less bare ground and more woody vegetation. Grazing affected vegetation immediately after grazing, but these effects weakened or disappeared by the end of the growing season. One exception to this overall pattern was forbs, which tended to be more abundant on grazed plots throughout the growing season. Overall, I found neutral effects of grazing on Northern Bobwhite nest and brood survival and habitat selection and neutral to positive benefits to the vegetation. Spring high-intensity short-duration grazing does not appear to be an effective tool to manage Northern Bobwhite nest or brood habitat in northeastern Colorado.