Conservation buffer practices implemented under U.S. Department of Agriculture (USDA) Farm Bill programs offer opportunities for enhancing breeding season habitat for farmland birds. Recently, CP33 (Habitat Buffers for Upland Birds) was added as a new continuous Conservation Reserve Program (CRP) practice designed to address habitat goals for northern bobwhite (Colinus virginianus) under the Northern Bobwhite Conservation Initiative. However, it is presumed that this practice will also benefit other birds. To evaluate potential benefits of CP33 field borders for farmland birds, we established a total of 89.0 km of experimental field borders (6.1-m wide) along agriculture field edges on three 405-ha farms in Clay and Lowndes counties, Mississippi. We used 200-m x 20-m strip transects to measure abundance and diversity of birds inhabiting bordered and non-bordered field edges. Indigo bunting (Passerina cyanea) and dickcissel (Spiza americana) abundances were nearly twofold greater along bordered field edges. However, mourning dove (Zenaida macroura), northern cardinal (Cardinalis cardinalis), and common grackle (Quiscalus quiscula) abundances did not differ between bordered and non-bordered field edges. Field borders adjacent to strip habitats (i.e., fencerows, drainage ditches) had greater total bird and redwinged blackbird (Agelaius phoeniceus) abundance than non-bordered edges adjacent to strip habitats. Species richness was greater along bordered than non-bordered edges. Within intensive agricultural landscapes where large-scale grassland restoration is impractical, USDA conservation buffer practices such as field borders (CP33) may be useful for enhancing local breeding bird richness and abundance. Key words: agriculture, breeding bird, CP33, Conservation Reserve Program, field border, Mississippi, strip transect, USDA
