In the southeastern U. S., longleaf pine savannas, important habitat for grassland birds, are subject to hurricanes and subsequent management. The intensity of tropical storms is predicted to increase with climate change, heightening the importance of understanding the effects of storm disturbance and salvage logging on species of concern such as Bachman's Sparrow (Peucaea aestivalis), a pine-savanna specialist. To determine how Bachman's Sparrow occupancy varies with the age and salvage history of pine stands, and to identify the vegetation and post-hurricane habitat features influencing stand occupancy, we surveyed Bachman's Sparrows in Mississippi savannas affected by Hurricane Katrina. Our point counts and vegetation surveys covered 89 stands over two breeding seasons, beginning one year after salvaging. Bachman's Sparrow occupancy was best predicted by increasing graminoid cover and density, with evidence of a quadratic effect reversing the relationship at high levels, decreasing tree density, also with a quadratic effect, decreasing shrub cover and density, and increasing abundance of downed tree crowns and upturned root balls. Occupancy was higher in mature stands, regardless of salvage, and in stands of seedlings and saplings, but lower in middle-aged stands. Our results suggest that disturbance from Katrina may have benefited Bachman's Sparrows by thinning trees, creating perches in the form of downed tree crowns, from which males sing, and creating refugia from predators in upturned root balls. Three years after the disturbance, salvage logging appeared to have no effect on occupancy, but such logging could be detrimental if it alters ground-layer vegetation severely.
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Vol. 112 • No. 4