Woodland habitats are scarce in the northern Great Plains and were historically concentrated along river corridors. Over the past century, riparian habitats in this area have been much reduced, but new woodland habitats in the form of farmstead woodlots and shelterbelts have appeared. We used mist net sampling and point counts to document richness and abundance of Neotropical migrant birds in farmstead woodlot habitats during spring and fall migrations (1996–1997) in southeastern South Dakota. A total of 668 individuals of 30 Neotropical migrant species (excluding the taxa Coccyzus, Troglodytes, Mimidae, Icterus and Pheucticus, in which migratory and non-migratory individuals were difficult to distinguish) was captured in 4342 net hours (using 9-m, rather than the standard 12-m mist nets) in spring. The corresponding fall totals (again using 9-m nets) were 3250 net h, 231 individuals and 29 species. If fall captures in a ragweed (Ambrosia trifida) patch occurring within the woodlot are included, however, the fall totals were 5107 net h, 1211 individuals and 29 species. Overall densities of Neotropical migrants from point counts were 1302 birds · km−2 in spring and 898 birds · km−2 in fall. Capture and point count data followed similar phenologies, with peak abundance during mid-May in spring and late August-early September in fall. Both methods indicated seasonal abundance differences for some species, with Swainson's thrush (Catharus ustulatus) and blackpoll warbler (Dendroica striata) more abundant in spring. Orange-crowned (Vermivora celata), Nashville (V. ruficapilla) and Wilson's (Wilsonia pusilla) warblers were more abundant in fall. Captures within the woodlot were evenly distributed among different microhabitats during spring migration, but fall captures occurred disproportionately in scrubby edge-related microhabitats, especially in ragweed, suggesting that seasonal shifts in microhabitat selection may occur within woodlots. Density and capture rate data were similar to previously reported values for riparian habitats in this area. Thus, a diverse assemblage of Neotropical migrants occurs in woodlots during migration, suggesting that woodlots are regularly used as stopover sites and supplement available natural woodland habitats along river corridors.
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Vol. 149 • No. 1