Interspecific Variation in Habitat Preferences of Grassland Birds Wintering in Southern Pine Savannas

Abstract

We studied wintering grassland bird communities in De Soto National Forest in southern Mississippi, USA to assess differences in bird communities and vegetation structure among different stand types. We also examined which vegetation structure and plant species predicted occurrence of Bachman's Sparrow (Peucaea aestivalis), Henslow's Sparrow (Ammodramus henslowii), and Sedge Wren (Cistothorus platensis). Bachman's Sparrows occurred only in uplands ( = 0.5 birds/ha) and stands managed for Red-cockaded Woodpeckers (Picoides borealis; = 0.9 birds/ha), Henslow's Sparrows occurred only in bogs ( = 3.8 birds/ha) and stands managed for Red-cockaded Woodpeckers ( = 2.1 birds/ha), while Sedge Wrens occurred in all stand types ( = 0.1–0.3 birds/ha). There were no significant differences among stand types in total bird densities for all three species combined. Dense, spatially uniform herbaceous cover and cover of Scleria muhlenbergii, a preferred food item in bogs, best predicted Henslow's Sparrow occurrence (39% s2 explained). Increased woody understory vegetation and decreased tree density best predicted Sedge Wren occurrence (17% s2 explained). Management for Henslow's Sparrows should focus on small-scale herbaceous ground-layer restoration in bogs. Bachman's Sparrows will respond more to thinning dense upland stands. Sedge Wrens and Bachman's Sparrows benefit from Red-cockaded Woodpecker management, whereas Henslow's Sparrow use of woodpecker stands is ephemeral.