Occurrence and nest survival of four thrush species on a managed central Appalachian forest.

摘要

The wood thrush (Hylocichla mustelina) is a species of concern in the central Appalachians, and is sympatric there with three related species, the American robin (Turdus migratorius), hermit thrush (Catharus guttatus), and veery (Catharus fuscescens). The objectives were to quantify use of mature forests and areas subjected to even-aged harvesting and partial harvesting by these four species by measuring their frequency of occurrence, nest survival, and nest site characteristics. The microhabitat characteristics were compared among the landcover types. During 2001-2003, point count surveys were conducted, monitored nests, and collected nest habitat data on a managed forest in West Virginia, USA. Land cover was digitized into five categories: deciduous and mixed mature forest, deciduous and mixed partial harvest, and even-aged regeneration harvest. Chi-square goodness-of-fit analysis with Bonferroni 95% confidence intervals indicated that deciduous partial harvests were more likely to be inhabited by wood thrushes. The other three species were less likely to occur in deciduous partial harvests, and veery had lower nest survival in partial harvests than in mature forest. Contrary to many published descriptions that suggest thrushes will not nest in even-aged harvests, a small number of all species but hermit thrushes did nest in this cover type, often near a residual canopy tree. Hermit thrushes were less likely to inhabit mature deciduous forest, even-aged harvests, and harvested edges but chose nesting areas in mature mixed forest that was disturbed by road building and the seeding of landings and skid trails >10 years ago. Microhabitat characteristics of landcovers did not differ overall. The results suggest a relationship with partial harvesting that is positive for wood thrush but negative for the other three species..