Avian Habitat Response to Grazing, Haying, and Biofuels Production in Native Warm-Season Forages in the Mid-South

Declines in grassland birds have been attributed to loss of habitat, habitat degradation, and changes in land management. In the Mid-South, pasture and hayfield management has focused on maintaining dense stands of non-native forages that do not provide suitable vegetative structure for grassland birds or northern bobwhite. Native warm-season grasses have been promoted for livestock forage and biofuels feedstock. However, little information exists on how these practices affect habitat for grassland songbirds or northern bobwhite in the Mid-South. We conducted a study of two cattle grazing treatments, two hay harvest treatments and a biofuels harvest treatment on vegetative structure for nesting and brood-rearing grassland birds and northern bobwhite in native warm-season grasses. We evaluated vegetative composition and structure during a typical nesting period for grassland songbirds and a typical brood-rearing period for northern bobwhite across Tennessee, 2010 and 2011. We also evaluated invertebrate availability in each grazing treatment. Full-season grazing created suitable structure for nesting and brood-rearing grassland songbirds and northern bobwhite, whereas early-season grazing only provided suitable nesting structure for these species through early summer. Hay and biofuels stands provided adequate nesting cover for grassland songbirds and northern bobwhite, and hay harvests in May and June enhanced structure for brood-rearing northern bobwhite by reducing grass height. However, hay harvests in May or June are likely to impact nesting success for grassland songbirds and northern bobwhite. NWSG planted for biofuels only did not provide suitable structure for northern bobwhite broods. We recommend big bluestem and indiangrass for hay production, as these species mature later and hay harvest is less likely to impact grassland bird reproductive success. In areas where grassland birds and northern bobwhite are a management concern, grazing is a better management tool than haying or biofuels production. We recommend full-season grazing in production stands of native warm-season forages to maximize benefits where grassland birds and northern bobwhite are a management concern.