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Cardueline finches (canaries, goldfinches, and rosefinches, etc.) vary widely in the degree to which their natural reproductive schedules track seasonal changes in photoperiod. In this study, we tested for photo-induction of reproductive development and photorefractoriness in males of three cardueline finch species: pine siskins (Carduelis pinus), common redpolls (Carduelis flammea), and white-winged crossbills (Loxia leucoptera). Exposure to long days (20L:4D) in winter induced gonadal growth and elevation of circulating luteinizing hormone (LH) in all three species. After 4.5 months on constant long days, gonadal regression was complete in redpolls and siskins, but only partial in crossbills. Feather molt was...
We initiated a three-year study to determine whether intense jet noise at Eielson Air Force Base is adversely affecting nesting songbird species. The Eielson Air Force Base was closed to air traffic during 2000, therefore our first year of study represents a control year. We compared nesting productivity, species diversity and abundance of birds at Eielson to an area without intense aircraft disturbance (Bonanza Creek). We also collected baseline data on avian nesting ecology and chronology to provide guidelines for the subsequent years of this study and because this information currently does not exist for landbirds in interior Alaska. Field technicians searched for nests and conducted point-count censuses in three...
We studied the distribution of birds breeding within five ecological landforms in Yukon-Charley Rivers National Preserve, a 10,194-km^sup 2^ roadless conservation unit on the Alaska-Canada border in the boreal forest zone. Passerines dominated the avifauna numerically, comprising 97% of individuals surveyed but less than half of the 115 species recorded in the Preserve. We used distance-sampling and discrete-removal models to estimate detection probabilities, densities, and population sizes across the Preserve for 23 species of migrant passerines and five species of resident passerines. Yellow-rumped Warblers (Dendroica coronata) and Dark-eyed Juncos (Junco hyemalis) were the most abundant species, together accounting...
Cardueline finches (canaries, goldfinches, and rosefinches, etc.) vary widely in the degree to which their natural reproductive schedules track seasonal changes in photoperiod. In this study, we tested for photo-induction of reproductive development and photorefractoriness in males of three cardueline finch species: pine siskins (Carduelis pinus), common redpolls (Carduelis flammea), and white-winged crossbills (Loxia leucoptera). Exposure to long days (20L:4D) in winter induced gonadal growth and elevation of circulating luteinizing hormone (LH) in all three species. After 4.5 months on constant long days, gonadal regression was complete in redpolls and siskins, but only partial in crossbills. Feather molt was...
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We studied the distribution of birds breeding within five ecological landforms in Yukon-Charley Rivers National Preserve, a 10,194-km^sup 2^ roadless conservation unit on the Alaska-Canada border in the boreal forest zone. Passerines dominated the avifauna numerically, comprising 97% of individuals surveyed but less than half of the 115 species recorded in the Preserve. We used distance-sampling and discrete-removal models to estimate detection probabilities, densities, and population sizes across the Preserve for 23 species of migrant passerines and five species of resident passerines. Yellow-rumped Warblers (Dendroica coronata) and Dark-eyed Juncos (Junco hyemalis) were the most abundant species, together accounting...
We initiated a three-year study to determine whether intense jet noise at Eielson Air Force Base is adversely affecting nesting songbird species. The Eielson Air Force Base was closed to air traffic during 2000, therefore our first year of study represents a control year. We compared nesting productivity, species diversity and abundance of birds at Eielson to an area without intense aircraft disturbance (Bonanza Creek). We also collected baseline data on avian nesting ecology and chronology to provide guidelines for the subsequent years of this study and because this information currently does not exist for landbirds in interior Alaska. Field technicians searched for nests and conducted point-count censuses in three...
    map background search result map search result map Estimation of Avian Population Sizes and Species Richness Across a Boreal Landscape in Alaska Physiological responses to photoperiod in three cardueline finch species Physiological responses to photoperiod in three cardueline finch species Estimation of Avian Population Sizes and Species Richness Across a Boreal Landscape in Alaska