Variation in Bachman's Sparrow home-range size at the Savannah River Site, South Carolina

Using radiotelemetry, we studied variation in home-range size of the Bachman's Sparrow (Aimophila aestivalis) at the Savannah River Site (SRS), South Carolina, during the 1995 breeding season. At SRS, sparrows occurred primarily in two habitats: mature pine habitats managed for Red-cockaded Woodpecker (Picoides borealis) and pine plantations 1 to 6 years of age. The mean 95% minimum convex polygon home-range size for males and females combined (n = 14) was 2.95 ha + 0.57 SE, across all habitats. Mean homerange size for males in mature pine stands (4.79 ha + 0.27, n = 4) was significantly larger than that in 4-year-old (3.00 ha + 0.31, n = 3) and 2-year-old stands (1.46 ha + 0.31, it = 3). Home-range sizes of paired males and females (it = 4 pairs) were similar within habitat type; mean distances between consecutive locations differed by habitat type and sex. We hypothesize that a gradient in food resources drives home-range dynamics.