Stopover Ecology of Autumn Landbird Migrants in the Boise Foothills of Southwestern Idaho
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چکیده
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 energetic condition within and among species and between two mist-netting sites located in different habitats. The proportion of birds recaptured ranged from zero to over 20%, and fewer than 5% of individuals were recaptured in most species. Mean minimum stopover durations from recapture data ranged from 1 to 10 days; most species averaged less than 6 days. Stopover duration estimates from open-population models were comparable but generally greater than estimates from recapture data. As found in stopover studies from other regions, stopover metrics varied within and among species in Idaho. However, most migrants in this study exhibited an ability to gain mass, evidenced both by recapture data and by regression of energetic condition against time since sunrise. These data imply that montane habitats in Idaho are suitable stopover sites. It follows that these habitats might serve an important role for many landbird migrants during the period of late summer molt and autumn migration, a time when many lowland areas of the West, including some riparian systems, are especially arid. We suggest that including montane nonriparian habitats in future stopover ecology studies will allow for a more complete understanding of migrant habitat needs in the West.
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...
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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 کاملMolt Strategies and Age Differences in Migration Timing Among Autumn Landbird Migrants in Southwestern Idaho
متن کامل
Molt Strategies and Age Differences in Migration Timing among Autumn Landbird Migrants in Southwestern Idaho
A .—Intraspecifi c pa erns of autumn migration timing are not well known, particularly in the western United States. Here, we (1) describe autumn migration timing and age ratios of landbird migrants in southwestern Idaho, (2) examine differences in timing among age and sex classes, and (3) demonstrate how prebasic molt strategies aff ect migration timing diff erences between age classes. As a g...
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تاریخ انتشار 2005