Golden Eagle (Aquila chrysaetos)

Katzner, Todd E.; Kochert, Michael N.; Steenhof, Karen; McIntyre, Carol L.; Craig, Erica H.; Miller, Tricia A.

doi:10.2173/bow.goleag.02

Cited by 49 publications

(81 citation statements)

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“…For example, bald and golden eagles differ in their prey selection and flight behaviors, which may affect how these species forage and use the landscape. Although bald eagles may feed on a variety of prey items, fish can be a dominant food source (Buehler 2020); golden eagles also feed on a variety of prey items, but they rely more heavily on terrestrial mammals such as rabbits and ground squirrels (Katzner et al 2020). Additionally, landscapes dominated by cultivated agricultural lands such as those found in the study area may also provide different foraging opportunities compared to the grassland or shrub‐steppe landscapes of the western United States.…”

Section: Discussionmentioning

confidence: 99%

Predicting Bald Eagle Collision at Wind Energy Facilities

et al. 2021

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Bald eagles (Haliaeetus leucocephalus) are currently protected in the United States under the Bald and Golden Eagle Protection Act of 1940 and Migratory Bird Treaty Act of 1918. Given these protections and the increasing development of wind energy throughout the United States, it is important for regulators and the wind industry to understand the risk of bald eagle collisions with wind turbines. Prior probability distributions for eagle exposure rates and collision rates have been developed for golden eagles (Aquila chrysaetos) by the United States Fish and Wildlife Service (USFWS). Given similar information has not been available for bald eagles, the current recommendation by the USFWS is to use the prior probability distributions developed using data collected on golden eagles to predict take for bald eagles. But some evidence suggests that bald and golden eagles may be at different risk for collision with wind turbines and the prior probability distributions developed for golden eagles may not be appropriate for bald eagles. We developed prior probability distributions using data collected at MidAmerican Energy Company's operating wind energy facilities in Iowa, USA, from December 2014 to March 2017 for bald eagle exposure rates and collision rates. The prior probability distribution for collision rate developed for bald eagles has a lower mean collision rate and less variability relative to that developed for golden eagles. We determined that the prior probability distributions specific to bald eagles from these operating facilities are a better starting point for predicting take for bald eagles at operating wind energy facilities in an agricultural landscape than those developed for golden eagles. © 2021 The Wildlife Society.

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Section: Discussionmentioning

confidence: 99%

Predicting Bald Eagle Collision at Wind Energy Facilities

et al. 2021

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“…We began visiting nests every 8–10 days when nestlings were able to thermoregulate (ca. 21 days old; Katzner et al , 2020 ) until nestlings were ~51 days old (typically 3 or 4 visits). After nestlings reached 51 days, we monitored nestlings from remote observation points every 3–5 days to determine survival and age at fledging.…”

Section: Methodsmentioning

confidence: 99%

“…High densities of golden eagles nest along the cliffs and rocky outcrops near the Snake River in southwestern Idaho ( Steenhof et al , 1997 ). Golden eagle nests often contain a diverse assemblage of ectoparasites ( Katzner et al , 2020 ), and the presence of H. inodorus has been documented in eagle nests in southwestern Idaho ( McFadzen et al , 1996 ), but the physiological consequences of H. inodorus infestation on eagle nestlings have not been studied. Understanding how H. inodorus affect golden eagle nestlings is important for the conservation and management of the species, which faces threats across its range from urbanization and human population growth ( Kochert and Steenhof, 2002 ).…”

Section: Introductionmentioning

confidence: 99%

Haematophagous ectoparasites lower survival of and have detrimental physiological effects on golden eagle nestlings

Dudek

Henderson

Hudon

et al. 2021

Conservation Physiology

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Haematophagous ectoparasites can directly affect the health of young animals by depleting blood volume and reducing energetic resources available for growth and development. Less is known about the effects of ectoparasitism on stress physiology (i.e. glucocorticoid hormones) or animal behaviour. Mexican chicken bugs (Haematosiphon inodorus; Hemiptera: Cimicidae) are blood-sucking ectoparasites that live in nesting material or nest substrate and feed on nestling birds. Over the past 50 years, the range of H. inodorus has expanded, suggesting that new hosts or populations may be vulnerable. We studied the physiological and behavioural effects of H. inodorus on golden eagle (Aquila chrysaetos) nestlings in southwestern Idaho. We estimated the level of H. inodorus infestation at each nest and measured nestling mass, haematocrit, corticosterone concentrations, telomere lengths and recorded early fledging and mortality events. At nests with the highest levels of infestation, nestlings had significantly lower mass and haematocrit. In addition, highly parasitized nestlings had corticosterone concentrations twice as high on average (42.9 ng/ml) than non-parasitized nestlings (20.2 ng/ml). Telomeres of highly parasitized female nestlings significantly shortened as eagles aged, but we found no effect of parasitism on the telomeres of male nestlings. Finally, in nests with higher infestation levels, eagle nestlings were 20 times more likely to die, often because they left the nest before they could fly. These results suggest that H. inodorus may limit local golden eagle populations by decreasing productivity. For eagles that survived infestation, chronically elevated glucocorticoids and shortened telomeres may adversely affect cognitive function or survival in this otherwise long-lived species. Emerging threats from ectoparasites should be an important management consideration for protected species, like golden eagles.

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“…Quality habitat in the vicinity of a power pole is generally a prerequisite for exposure to electrocution risk (Tinto et al 2010;Dwyer et al 2014;Bedrosian et al 2020). In North America, both eagle species can be found in a wide variety of landscapes including grassland, shrublands, tundra, desert, and forested regions (Buehler 2020, Katzner et al 2020, though electrocution risk appears to be greater for golden eagles in unforested landscapes with few natural perches and greater for bald eagles when perched adjacent to waterbodies (Mojica et al 2018, Watts et al 2015. High-quality habitats for golden eagles are relatively undeveloped with abundant prey, predominantly sciurid and leporid species (Bedrosian et al 2017;Katzner et al 2020).…”

Section: Habitatmentioning

confidence: 99%

Importance of Power Pole Selection When Retrofitting for Eagle Compensatory Mitigation

Mojica

Eccleston

Harness

2021

Journal of Fish and Wildlife Management

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In the United States, the bald eagle Haliaeetus leucocephalus and golden eagle Aquila chrysaetos are federally managed to ensure the species are stable or increasing while allowing for potentially negative effects from anthropogenic sources. Compensatory mitigation, through retrofitting high-risk power poles to reduce electrocutions, can be used to offset negative effects, enabling the U.S. Fish and Wildlife Service to achieve their management objectives of species stability and persistence . Regulators, permit holders, electric utilities, and consultants lack an objective and repeatable method for discriminating between high-risk and low-risk power poles. To illustrate the importance of accurately identifying and retrofitting high-risk poles, we compare conservation benefits among three retrofitting project scenarios: a) high-risk poles only, b) a circuit of both low- and high-risk poles, and c) low-risk poles only. We assert that, in the absence of a common definition of high-risk power poles applied uniformly across the landscape, mitigation approved by the U.S. Fish and Wildlife Service could fall short of its intended value and be unable to meet management objectives. We define high-risk poles in the context of compensatory mitigation as poles in high-quality bald or golden eagle habitat with a relative risk index ≥0.40 based on number of phases, number of jumper wires, and presence of pole grounding. We estimate that the conservation benefit of retrofitting a high-risk pole is at least 5.25 times greater than the benefit of retrofitting a low-risk pole. In the long-term, if compensatory mitigation intended to achieve management objectives falls short of its assumed conservation value, the U.S. Fish and Wildlife Service could be forced to limit future permit authorizations until bald or golden eagles can recover from incorrectly calculated conservation benefits. To avoid that negative outcome, we recommend the U.S. Fish and Wildlife Service set consistent and transparent standards for identifying poles to count as compensatory mitigation credit using our proposed definition of a high-risk power pole.

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Golden Eagle (Aquila chrysaetos)

Cited by 49 publications

References 0 publications

Predicting Bald Eagle Collision at Wind Energy Facilities

Predicting Bald Eagle Collision at Wind Energy Facilities

Haematophagous ectoparasites lower survival of and have detrimental physiological effects on golden eagle nestlings

Importance of Power Pole Selection When Retrofitting for Eagle Compensatory Mitigation

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