Golden Eagle Nest Site Selection and Habitat Suitability Modeling Across Two Ecoregions in Southern Nevada
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Because of perceived declines in populations of the golden eagle (Aquila chrysaetos) in the western United States, the United States Fish and Wildlife Service (USFWS) closely monitors population trends throughout their range. An inventory of golden eagles in two ecosystems in Nevada (the northern Mojave Desert and southern Great Basin) was conducted from 2011-2014 with the objectives to: 1) locate and determine the abundance of golden eagle nest sites (active and inactive) in two eco-regions (Mojave Desert and Great Basin); 2) quantify golden eagle nest density and abundance within the designated study sites; 3) determine the size of territories of nesting golden eagles; 4) determine the influence of nest site variables on acquired data; 5) develop a habitat suitability model using nest site variables to delineate areas with high probability for nest site selection. Cliff and canyon habitats of the southern Great Basin and northern Mojave Desert ecoregions were surveyed for active and inactive nests of golden eagles and to measure nest site parameters by helicopter in 2011-2014. Nest site parameters used for analysis were: general location, mountain range, cliff height, viewshed, soils, geology, elevation, aspect, slope, habitat, use, productivity and distances to the nearest road and water. A suitability index was created using these parameters and the program MaxEnt to map potential nesting habitats within the boundaries of my study sites. A total of 96 nest sites (old/abandoned and newly decorated) were located and analyzed. During the four years, 27 active nests produced 36 fledglings. Two nests were occupied for three years and three nests had double occupancy in a year. Nesting habitat variables that were chosen for the final predictive model include: elevation, slope, distance to nearest road and distance to water. The results of my project will aid in establishing a monitoring program to provide guidance in avoiding and minimizing disturbances and other kinds of future “take” by federal agencies requiring consultation with USFWS.