Breeding Ecology and Habitat Suitability of Ferruginous Hawks (Buteo regalis) in Southern Idaho

Ferruginous hawks inhabit grassland and shrub steppe ecosystems in the western and central United States. In the Great Basin, widespread habitat alterations are suggested as drivers of population declines and Ferruginous hawks are listed as a “Type II Sensitive Species” by the Bureau of Land Management. To better understand the characteristics of southern Idaho’s breeding population and its conservation needs we established a long-term collaborative monitoring program to provide baseline data on the ecology and population demography of Ferruginous hawks in and around the Morley Nelson Snake River Birds of Prey National Conservation Area. We monitored 76 breeding territories and documented territory occupancy and productivity between March and July 2017. We used a multivariate generalized linear model with model selection procedures to evaluate the relative importance of ecological attributes and human disturbance agents on Ferruginous hawk nest breeding success. Here, we present the results of our monitoring and preliminary models, and discuss their implications for Ferruginous hawk breeding ecology and management

Mercury Contamination in Idaho Bald Eagles, \u3cem\u3eHaliaeetus leucocephalus\u3c/em\u3e

Because mercury contamination is potentially threatening to bald eagle (Haliaeetus leucocephalus) populations, we collected molted feathers at nests to determine the level of contamination in bald eagles in the state of Idaho, USA. Eagle feathers contained measurable amounts of cadmium (Cd), chromium (Cr), selenium (Se), lead (Pb), as well as mercury (Hg). Cadmium, Cr, Se, and Pb levels averaged 0.17, 4.68, 2.02, and 1.29 mg/kg dry weight, respectively, and were at or below concentrations indicated as causing reproductive failure in bald eagles. Mercury contamination was found to be the highest averaging 18.74 mg/kg dry weight. Although a concentration of only 7.5 mg/kg dry weight Hg in bird feathers can cause reduced productivity and even sterility, all of the eagles we sampled bred successfully and the population of bald eagles continues to grow annually throughout the state