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Melanism (dark coloration) is a condition resulting from a greater than normal expres-sion of the eumelanin pigments in the plumage (Gill 1990). The dark coloration can be advantageous to raptors by increasing the feathers’ resistance to bacterial degradation (Goldstein et al. 2004). conversely, abnormally dark pigmentation can reduce success in pairing by disguising key species-identification cues (García 2003) and decrease lifetime reproductive success by increasing mortality (krüger and lindström 2001). Polymorphism in color, of which melanism is one example, occurs in at least 3.5% of avian species worldwide and in 22% of raptors of the family Accipitridae (harriers, hawks, eagles, kites, and Old World vultures;...
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FY2011Research is showing that populations of wintering raptors, including Northern Harriers, Rough-Legged Hawks, Prairie Falcons, American Kestrels. Red-Tailed Hawks and Golden Eagles, have stayed relatively constant in the last 20 years are being used by the Bureau of Land Management and Idaho Army National Guard in developing raptor conservation management practices. The American Wind and WildlifeInstitute will also use the results for their wind energy siting support tools.
There is widespread evidence that multiple drivers of global change, such as habitat degradation, invasive species, and climate change, are influencing wildlife. Understanding how these drivers interact with and affect species may be difficult because outcomes depend on the magnitude and duration of environmental change and the life history of the organism. In addition, various environmental drivers may be evaluated and managed at different spatial scales. We used a historical dataset from 1991 to 1994 and current information from 2010 to 2012 to examine whether occupancy patterns of wintering raptors were consistent with regional changes in distribution or habitat conditions within a local management unit, the...
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In addition to current distribution of each bird species, this map shows their current and near-term status within the ecoregion. Current, long-term, and summary bioclimate data is also include for several of these bird species. The input datasets used in the distribution model are also included. These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users...
Studies of multiple taxa across broad-scales suggest that species distributions are shifting poleward in response to global climate change. Recognizing the influence of distribution shifts on population indices will be an important part of interpreting trends within management units because current practice often assumes that changes in local populations reflect local habitat conditions. However, the individual- and population-level processes that drive distribution shifts may occur across a large, regional scale and have little to do with the habitats within the management unit. We examined the latitudinal center of abundance for the winter distributions of six western North America raptor species using Christmas...
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In addition to current distribution of each bird species, this map shows their current and near-term status within the ecoregion. Current, Long-term, and summary bioclimate data is also include for several of these bird species. The input datasets used in the distribution model are also included. These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users...


    map background search result map search result map Current Versus Historical Trends in Habitat Use by Wintering Raptors in the Snake River Birds of Prey National Conservation Area BLM REA MBR 2010 Terrestrial Species Birds Status - Northern Harrier BLM REA CBR 2010 Terrestrial Species Birds Status - Northern Harrier BLM REA MBR 2010 Terrestrial Species Birds Status - Northern Harrier Current Versus Historical Trends in Habitat Use by Wintering Raptors in the Snake River Birds of Prey National Conservation Area BLM REA CBR 2010 Terrestrial Species Birds Status - Northern Harrier