Midwest Fish & Wildlife Conference 2017

AUTHORS: Bram H.F. Verheijen, Brett K. Sandercock - Division of Biology, Kansas State University

ABSTRACT: Many species of songbirds in North America have been declining in population numbers. Ongoing declines have been linked to habitat loss and fragmentation, and increased landscape homogeneity caused by agricultural intensification. To counter ongoing declines of grassland songbirds, we tested the potential benefits of patch-burn grazing management, which creates high levels of heterogeneity in vegetative structure. Recent studies found that patch-burn grazing management increases bird diversity and nest survival in Dickcissels (Spiza americana), but the impacts on fledglings, and total reproductive output of grassland songbirds, have been largely ignored. Due to their limited initial movements, the survival of altricial young after fledging is likely influenced by local variation in habitat structure, food abundance, and predator pressure. To assess the effects of heterogeneity in vegetative structure on the survival and movements of fledgling Dickcissels, a species of conservation concern, we applied transmitters to 48 fledglings at five experimental units at Konza Prairie LTER, Kansas. We found a potential conflict between the nest and fledgling stage of Dickcissels. Although nest survival tended to be highest in treatments with low heterogeneity, fledglings showed high mortality and actively moved away from those treatments. Rangeland management could potentially affect predators of nests and fledglings in species-specific ways, potentially leading to life-stage specific responses to management in Dickcissels. Conflicts in habitat requirements among life-stages could have important implications for how we structure and evaluate conservation efforts. Moreover, a heterogeneous landscape could provide songbirds with a mosaic of habitats that could maximize both nest and fledgling survival.