A Comparison of Shrub-dominated and Forested Habitat Use by Spring Migrating Landbirds in Northeastern Pennsylvania
نویسنده
چکیده
Long-term datasets reveal declines in many populations of landbird migrants, with declines especially evident in shrub-nesting species. Moreover, transitional shrub-dominated habitats are becoming scarce, reducing breeding habitat for these species. Because migrants often occupy habitats en route similar to those used in the breeding season, the persistence of shrub-dominated habitats may be especially critical for these species during passage. Because little is known about migrant-habitat relationships, especially at inland, unforested stopover sites, we compared the importance of forested and upland shrub-dominated habitat to spring migrating landbirds by comparing: (1) temporal and habitat-related variation in resource abundance, and (2) migrant use of forested vs. shrub-dominated habitat during stopover. We collected data on bird-habitat relationships and invertebrate abundance from both habitats at two sites in or near Lackawanna State Park, Lackawanna County, Pennsylvania. We captured and counted more short-distance and long-distance migrants in shrub habitat (256 birds per 1000 mist-net hours and seven birds per 100 m of survey transect) than in forested habitat (67 birds per 1000 mist-net hours and three birds per 100 m of transect), and shrub habitat contained a somewhat greater diversity of migrants (H′ = 4.0 vs. 3.9). We also measured greater flying invertebrate biomass in shrub vs. forested habitat, although there was no difference in flightless invertebrate biomass between the two habitats. Our results support the hypothesis that migrant habitat use reflects spatial differences in resource abundance and indicate that shrubdominated habitats may be important stopover habitat for landbird migrants.
منابع مشابه
Stopover Habitat along the Shoreline of Northern Lake Huron, Michigan: Emergent Aquatic Insects as a Food Resource for Spring Migrating Landbirds
A .—Recent work in Michigan’s eastern Upper Peninsula suggests that terrestrial areas bordering northern Lake Huron provide important stopover habitat for spring migrating landbirds, principally because of the presence of emergent aquatic midges (Diptera: Chironomidae). Migrants were concentrated in lakeshore habitats abundant with midges during spring migration. American Redstarts (Setophaga r...
متن کاملAutumn Landbird Communities in the Boise Foothills and Owyhee Mountains of Southwestern Idaho
Identifying important stopover areas is a critical step in conservation and management of migratory birds, and relatively little effort has been directed toward this task in Idaho or the Intermountain West. We used mist-net captures to describe the relative abundance, species richness, and community similarity of autumn migrant landbirds in the Boise Foothills and Owyhee Mountains of southweste...
متن کاملHabitat Associations of Migrating and Overwintering Grassland Birds in Southern Texas
We report on the habitat associations of 21 species of grassland birds overwintering in or migrating through southern Texas, during 1991-1992 and 1992-1993. Ninety percent of our grassland bird observations were made during winter and spring, and only 10% occurred during fall. Grassland species made up a high proportion of the total bird densities in grassland and shrub-grassland habitats, but ...
متن کاملFood Availability, Foraging Behavior, and Diet of Autumn Migrant Landbirds in the Boise Foothills of Southwestern Idaho
Food availability and acquisition are critical components of a stopover site’s suitability, but we know relatively little about how changes in food availability affect the stopover ecology of migrating landbirds. we examined fruit and arthropod availability in three habitats, studied foraging behavior and diet, and investigated use versus availability for passerines migrating through southweste...
متن کاملLiving with Aliens: Effects of Invasive Shrub Honeysuckles on Avian Nesting
Invasive species have come to the forefront of conservation biology as a major threat to native biodiversity. Habitats dominated by shrub honeysuckles (Lonicera spp.) in the United States have been characterized as "ecological traps" by ecologists. Here we tested this hypothesis by investigating the effects of shrub honeysuckles on the nesting ecology of native birds in seven study sites in cen...
متن کامل