Modeling spatial variation in density of golden eagle nest sites in the western United States

• Published in: PloS one Vol. 14; no. 9; p. e0223143
• Main Authors: Dunk, Jeffrey R, Woodbridge, Brian, Lickfett, Todd M, Bedrosian, Geoffrey, Noon, Barry R, LaPlante, David W, Brown, Jessi L, Tack, Jason D
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30-09-2019; Public Library of Science (PLoS)
• Subjects: Analysis; Animals; Aquila chrysaetos; Biology and Life Sciences; Breeding; Colonies & territories; Conservation; Conservation of Natural Resources - methods; Demography; Density; Eagles - physiology; Earth Sciences; Ecology and Environmental Sciences; Ecosystem biology; Ecosystems; Electrocutions; Engineering and Technology; Environmental protection; Female; Genetic variation; Geospatial data; Green technology; Habitats; Humans; Land use; Land use management; Lead poisoning; Male; Midwestern United States; Mitigation; Modelling; Models, Statistical; Nesting Behavior - physiology; Northwestern United States; People and places; Population; Population Dynamics - statistics & numerical data; Recreational use; Reproduction - physiology; Southwestern United States; Spatial data; Wildfowl; Wildlife conservation; Wind power; Midwestern United States; Northwestern United States; Southwestern United States; United States; Western states; United States > US; Colorado
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0223143

In order to contribute to conservation planning efforts for golden eagles (Aquila chrysaetos) in the western U.S., we developed nest site models using >6,500 nest site locations throughout a >3,483,000 km2 area of the western U.S. We developed models for twelve discrete modeling regions, and estimated relative density of nest sites for each region. Cross-validation showed that, in general, models accurately estimated relative nest site densities within regions and sub-regions. Areas estimated to have the highest densities of breeding golden eagles had from 132-2,660 times greater densities compared to the lowest density areas. Observed nest site densities were very similar to those reported from published studies. Large extents of each modeling region consisted of low predicted nest site density, while a small percentage of each modeling region contained disproportionately high nest site density. For example, we estimated that areas with relative nest density values <0.3 represented from 62.8-97.8% ([Formula: see text] = 82.5%) of each modeling area, and those areas contained from 14.7-30.0% ([Formula: see text] = 22.1%) of the nest sites. In contrast, areas with relative nest density values >0.5 represented from 1.0-12.8% ([Formula: see text] = 6.3%) of modeling areas, and those areas contained from 47.7-66.9% ([Formula: see text] = 57.3%) of the nest sites. Our findings have direct application to: 1) large-scale conservation planning efforts, 2) risk analyses for land-use proposals such as recreational trails or wind power development, and 3) identifying mitigation areas to offset the impacts of human disturbance.