Geographic locations (Alaska = AK, California = CA, Idaho = ID) where each of 8 mitochondrial D-loop region haplotypes were identified.

<p>The nucleotide variation of the 8 haplotypes at each of 7 variable sites is also listed.</p

Nuclear and Mitochondrial DNA Analyses of Golden Eagles (<i>Aquila chrysaetos canadensis</i>) from Three Areas in Western North America; Initial Results and Conservation Implications

<div><p>Understanding the genetics of a population is a critical component of developing conservation strategies. We used archived tissue samples from golden eagles (<i>Aquila chrysaetos canadensis</i>) in three geographic regions of western North America to conduct a preliminary study of the genetics of the North American subspecies, and to provide data for United States Fish and Wildlife Service (USFWS) decision-making for golden eagle management. We used a combination of mitochondrial DNA (mtDNA) D-loop sequences and 16 nuclear DNA (nDNA) microsatellite loci to investigate the extent of gene flow among our sampling areas in Idaho, California and Alaska and to determine if we could distinguish birds from the different geographic regions based on their genetic profiles. Our results indicate high genetic diversity, low genetic structure and high connectivity. Nuclear DNA Fst values between Idaho and California were low but significantly different from zero (0.026). Bayesian clustering methods indicated a single population, and we were unable to distinguish summer breeding residents from different regions. Results of the mtDNA AMOVA showed that most of the haplotype variation (97%) was within the geographic populations while 3% variation was partitioned among them. One haplotype was common to all three areas. One region-specific haplotype was detected in California and one in Idaho, but additional sampling is required to determine if these haplotypes are unique to those geographic areas or a sampling artifact. We discuss potential sources of the high gene flow for this species including natal and breeding dispersal, floaters, and changes in migratory behavior as a result of environmental factors such as climate change and habitat alteration. Our preliminary findings can help inform the USFWS in development of golden eagle management strategies and provide a basis for additional research into the complex dynamics of the North American subspecies.</p></div

Results of the mtDNA AMOVA in the California and Idaho golden eagle populations.

<p>Results of the mtDNA AMOVA in the California and Idaho golden eagle populations.</p

Parsimony network of eight D-loop mitochondrial DNA haplotypes for 60 golden eagle summer resident samples (Idaho = 21, California = 23, Alaska = 11, Canada = 5) from this study and others [9,17].

<p>Node size is equivalent to the number of individuals with each haplotype. Each line is equivalent to one base pair change between haplotypes with the exception of the line between GOEA04 and GOEA06, which is equivalent to two base pair changes. Light gray = Alaska, dark gray = California, black = Idaho and white = Canada.</p

Quantifying the demographic cost of human-related mortality to a raptor population

<div><p>Raptors are exposed to a wide variety of human-related mortality agents, and yet population-level effects are rarely quantified. Doing so requires modeling vital rates in the context of species life-history, behavior, and population dynamics theory. In this paper, we explore the details of such an analysis by focusing on the demography of a resident, tree-nesting population of golden eagles (<i>Aquila chrysaetos</i>) in the vicinity of an extensive (142 km²) windfarm in California. During 1994–2000, we tracked the fates of >250 radio-marked individuals of four life-stages and conducted five annual surveys of territory occupancy and reproduction. Collisions with wind turbines accounted for 41% of 88 uncensored fatalities, most of which were subadults and nonbreeding adults (floaters). A consistent overall male preponderance in the population meant that females were the limiting sex in this territorial, monogamous species. Estimates of potential population growth rate and associated variance indicated a stable breeding population, but one for which any further decrease in vital rates would require immigrant floaters to fill territory vacancies. Occupancy surveys 5 and 13 years later (2005 and 2013) showed that the nesting population remained intact, and no upward trend was apparent in the proportion of subadult eagles as pair members, a condition that would have suggested a deficit of adult replacements. However, the number of golden eagle pairs required to support windfarm mortality was large. We estimated that the entire annual reproductive output of 216–255 breeding pairs would have been necessary to support published estimates of 55–65 turbine blade-strike fatalities per year. Although the vital rates forming the basis for these calculations may have changed since the data were collected, our approach should be useful for gaining a clearer understanding of how anthropogenic mortality affects the health of raptor populations, particularly those species with delayed maturity and naturally low reproductive rates.</p></div

Golden eagle life cycle.

<p>Golden eagle life cycle.</p

High quality nesting habitat for golden eagles in the Diablo Range, California.

<p>High quality nesting habitat for golden eagles in the Diablo Range, California.</p

The Altamont Pass windfarm as viewed from its southern boundary in April 1995.

<p>The dense configurations of small turbines in this photo are currently being replaced by fewer, larger, and more widely spaced machines.</p

Probability of annual survival () for four stage-classes of golden eagles radio-marked in the vicinity of the Altamont Pass Wind Resource Area, California, 1994–2000.

<p>We show survival estimates with and without turbine-related and known human-caused deaths included in the analysis. All undiagnosed deaths were treated as "natural" so as to obtain a maximum estimate of natural mortality (see text). No juveniles were killed by turbine blade-strikes.</p

Ages of breeding golden eagles at territories within 30 km of the Altamont windfarm.

<p>The asterisk indicates that the calculation included two individuals of uncertain age and therefore gave the maximum possible representation of subadults for that year. Note that yearly variation in the number of aged eagles reflects differences in sampling effort rather than population.</p