Landscape-level Analyses of Henslow's Sparrow (Ammodramus henslowii) Abundance in Reclaimed Coal Mine Grasslands

Abstract

Abstract Henslow's sparrow (Ammodramus henslowii) abundance, measured as average number of males at point counts, varied within and among reclaimed mine grasslands of southwestern Indiana. The 19 mine grasslands studied range from about 100 to 3200 ha and vary in landscape structure and composition both within the mines and in relation to the surrounding area. Nevertheless, few landscape-level attributes of mine grasslands were related to Henslow's sparrow abundance. Landscape composition (e.g., percent forest or grassland cover), in particular, had a negligible effect on Henslow's sparrow abundance. Neither habitat patch size nor shape had a significant effect on Henslow's sparrow abundance, but these birds tended to avoid habitat edges. Variation in Henslow's sparrow abundance was, however, influenced by the composition and structure of local vegetation. The relative “landscape insensitivity” of Henslow's sparrows probably reflects the large area of mine grasslands rather than a true lack of landscape-s...