Thesis (M.S.)--Boise State University, 2009. / Title from t.p. of PDF file (viewed Feb. 23, 2010). Includes abstract. Includes bibliographical references.

Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on June 16, 2008). Includes bibliographical references (p. 52-55).

Thesis (M.S.)--Boise State University, 2009. / Includes abstract. Includes bibliographical references.

Forty-three and 54 Ferruginous hawk (Buteo regalis) pairs were found occupying territories in northern Utah and southeastern Idaho during 1972 and 1973, respectively. Of these 38 and 27 nesting pairs laid eggs. Nesting success was 77.1 percent in 1972 and 74.6 percent in 1973. for successful nests, an average of 2.9 and 2.6 young hatched and 2.7 and 2.3 young fledged during the respective years. This population is reproductively comparable to others in Utah and Colorado. Analysis of prey items collected from the nests indicated that black-tailed jack-rabbits (Lepus californicus) constitute 86 percent of the biomass (by weight) of three major prey species consumed by ferruginous hawks in this area. Jackrabbit density may be a major determinant of the number of young produced in a given year. Weight gained by the nestlings showed a marked sexual dimorphism. Female fledgelings weighed up to 1.43 times as much as males. Criteria were developed for sexing ferruginous hawks by measuring the diameter of the hallux. Mortality of 17 birds from the study area was recorded, of which 47 percent were immature birds. A total of 108 fledglings were banded and marked with color-coded patagial wing markers. Band reports of five (10 percent) of these birds were received. Utah juniper (Juniperus osteosperma) provided nest sites for 96.0 percent of the nests while three percent were built on the ground. Plant community types were determined at 63 nesting sites from aerial photographs. Dominant vegetation around nest sites were desert shrub types and crested wheatgrass (Agropyron cristatum) seedings. The possible impact of land management practices on ferruginous hawks is discussed.

Development and climate change in the sagebrush habitats are causing population declines of North American hawks and eagles. For these species, understanding the landscape features that are preferred for nesting and the prey they consume in sagebrush habitats are important in developing conservation plans. Specifically, we know little of the preferred nest-sites and diet of Ferruginous Hawks (Buteo regalis) and Golden Eagles (Aquila chrysaetos) many locales. In our study, we determined the landscape characteristics associated with nest sites for these two raptor species in the Uintah Basin, UT to predict where nests may occur in our study area. We found that slope, elevation, distance to nearest oil and gas wells, geology, and facing south were the most important variables in characterizing Golden Eagle nest-sites. Elevation, slope, vegetation type, and distance to nearest oil and gas wells were the most important variables in characterizing Ferruginous Hawk nest-sites. In addition, we looked at the diets of Golden Eagles, Ferruginous Hawks, and Northern Goshawks in the Uinta Basin, UT using a genetic analysis method novel to raptors. We found species consistent with previous diet studies and detected prey items not previously reported, including the Western Whiptail (Aspidocelis tigris), Domestic Cow (Bos Taurus), Domestic Pig (Sus scrofa), and Rock Bass (Amboplites rupestris) within Ferruginous Hawk samples. Results from our study can provide managers with tools to better survey for nest-sites and to provide an alternative method of diet analysis to provide insight into prey species important to these raptors.