Food Availability, Foraging Behavior, and Diet of Autumn Migrant Landbirds in the Boise Foothills of Southwestern Idaho
نویسندگان
چکیده
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 southwestern idaho in autumn. hemiptera dominated foliage-dwelling arthropod communities in all three habitats, whereas hymenoptera were most numerous among ground-dwelling arthropods. mountain shrubland had relatively high biomass of both ground-dwelling and foliage-dwelling arthropods, whereas conifer forest had high biomass of foliage-dwelling arthropods only and shrubsteppe had high biomass of ground-dwelling arthropods only. Species’ foraging behavior varied, but most species foraged in mountain shrubland more often than expected by chance. diets of most species included a high proportion of certain hemiptera and hymenoptera with smaller proportions of Coleoptera, diptera, and heteroptera; Coleoptera and some hemiptera were consistently preferred by most species. importantly, all 19 bird species examined consumed some fruit, and this is the first documentation of frugivory for two warbler species. These data point to the importance of several arthropod taxa, especially the hemiptera and hymenoptera, and fruits to landbirds migrating in mountain shrubland in autumn. Finally, we found no effect of annual variation of fruit or arthropod abundance on migrants’ energetic condition, suggesting that food was sufficient for mass gain in all years of this study and/or that foraging behavior may be plastic enough to allow birds to gain mass despite annual differences in food availability.
منابع مشابه
Autumn 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, Relative Abundance, and Species Richness of Autumn Landbird Migrants in Southwestern Idaho
We used count surveys and mist-net captures to compare habitat associations, relative abundance, species richness, and community similarity of migrant landbirds among four major habitats in the Boise Foothills of southwestern Idaho. Count surveys were conducted from August through October 1997–2000 in conifer forest, mountain shrubland, shrubsteppe, and riparian shrubland. We compared bird dete...
متن کاملStopover Ecology of Autumn Landbird Migrants in the Boise Foothills of Southwestern Idaho
The topography of western North America provides a complex landscape for landbird migrants, and stopover patterns in this region are poorly understood. We examined seven years of stopover data (1997–2003) from a montane area in southwestern Idaho to determine whether this area provides suitable stopover habitat. We compared the proportion of birds recaptured, stopover duration, and changes in e...
متن کاملStopover 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 کامل