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J C Knobel - One of the best experts on this subject based on the ideXlab platform.
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the bald and Golden Eagle protection act species based legal protection and the danger of misidentification
Potchefstroom Electronic Law Journal, 2016Co-Authors: J C KnobelAbstract:The Bald and Golden Eagle Protection Act of 1940 bestows legal protection on two North American Eagle species in the United States of America. The Act was originally aimed at the legal protection of only one species: the Bald Eagle Haliaeetus leucocephalus, the national symbol of the USA. Later the Act was amended to extend protection also to the Golden Eagle Aquila chrysaetos. The Bald Eagle was an Endangered Species, but the Golden Eagle was not formally listed as Endangered nationwide in the USA. One of the reasons for extending legal protection to the Golden Eagle under the Act was to strengthen the legal protection of the Bald Eagle, because immature Bald Eagles were being misidentified as Golden Eagles and shot. Additional factors relating to Golden Eagle mortality also made legal protection of the Golden Eagle desirable. The danger that a rare and legally protected species can be misidentified and mistaken for a more common and unprotected species can therefore serve as a reason for bestowing legal protection on the more common species as well. Other factors may also indicate that legal protection of the more common species is desirable, making the case more compelling. If this line of reasoning is applied in respect of South African birds of prey, a strong case can be made in favour of extending legal protection under the national biodiversity legislation to more species than the small number of species currently enjoying such protection. Species that are listed as Vulnerable under South African national biodiversity legislation may be misidentified as species that are not subject to such protection. Additional factors are also present that make such an extension of legal protection desirable.Keywords: environmental law; legal protection; biodiversity; species; misidentification; Bald Eagle; Golden Eagle; bird of prey; raptor; South Africa
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the bald and Golden Eagle protection act species based legal protection and the danger of misidentification
Social Science Research Network, 2015Co-Authors: J C KnobelAbstract:The Bald and Golden Eagle Protection Act of 1940 bestows legal protection on two North American Eagle species in the United States of America. The Act was originally aimed at the legal protection of only one species: the Bald Eagle Haliaeetus leucocephalus, the national symbol of the USA. Later the Act was amended to extend protection also to the Golden Eagle Aquila chrysaetos. The Bald Eagle was an Endangered Species, but the Golden Eagle was not formally listed as Endangered nationwide in the USA. One of the reasons for extending legal protection to the Golden Eagle under the Act was to strengthen the legal protection of the Bald Eagle, because immature Bald Eagles were being misidentified as Golden Eagles and shot. Additional factors relating to Golden Eagle mortality also made legal protection of the Golden Eagle desirable. The danger that a rare and legally protected species can be misidentified and mistaken for a more common and unprotected species can therefore serve as a reason for bestowing legal protection on the more common species as well. Other factors may also indicate that legal protection of the more common species is desirable, making the case more compelling. If this line of reasoning is applied in respect of South African birds of prey, a strong case can be made in favour of extending legal protection under the national biodiversity legislation to more species than the small number of species currently enjoying such protection. Species that are listed as Vulnerable under South African national biodiversity legislation may be misidentified as species that are not subject to such protection. Additional factors are also present that make such an extension of legal protection desirable.
Jason D Tack - One of the best experts on this subject based on the ideXlab platform.
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ecosystem processes land cover climate and human settlement shape dynamic distributions for Golden Eagle across the western us
Animal Conservation, 2020Co-Authors: Jason D Tack, Barry R Noon, Zachary H Bowen, Brad C FedyAbstract:Species–environment relationships for highly mobile species outside of the breeding season are often highly dynamic in response to the collective effects of ever‐changing climatic conditions, food resources, and anthropogenic disturbance. Capturing dynamic space‐use patterns in a model‐based framework is critical as model inference often drives place‐based conservation planning. We applied dynamic occupancy models to broad‐scale Golden Eagle Aquila chrysaetos survey data collected annually from 2006 to 2012 during the late summer post‐fledging period in the western US. We defined survey sites as 10 km transect segments with a 1 km buffer on either transect side (n = 3540). Derived estimates of occupancy were low (4.4–7.9%) and turnover rates – the probability that occupied sites were newly occupied – were high (88–94%), demonstrating that annual transiency in occupancy dominates late summer behavior for Golden Eagles. Despite low philopatry during late summer, variation in Golden Eagle occupancy could be explained by a suite of land cover and annual‐varying covariates including gross primary productivity, drought severity, and human disturbance. Our summary of 13 years of predicted occupancy by Golden Eagles across the western United States identified areas that are consistently used and that may contribute significantly to Golden Eagle conservation. Restricting development and targeting mitigation efforts in these areas offers practitioners a framework for conservation prioritization.
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no substitute for survival perturbation analyses using a Golden Eagle population model reveal limits to managing for take
Journal of Raptor Research, 2017Co-Authors: Jason D Tack, Barry R Noon, Zachary H Bowen, Lauren Strybos, Bradley C FedyAbstract:Abstract Conserving populations of long-lived birds of prey, characterized by a slow life-history (e.g., high survival and low reproductive output), requires a thorough understanding of how variation in their vital rates differentially affects population growth. Stochastic population modeling provides a framework for exploring variation in complex life histories to better understand how environmental and demographic variation within individual vital rates affects population dynamics. Specifically, we used life-stage simulation analysis (LSA) to identify those life-history characteristics that most affect population growth and are amenable to management actions. The Golden Eagle (Aquila chrysaetos) is a wide-ranging raptor of conservation concern, which has been adopted as a focal species for conservation planning. Golden Eagle population trends in western North America currently appear stable. Yet an expanding human footprint that may increase mortality stimulated our investigation into the ability of pop...
Brad C Fedy - One of the best experts on this subject based on the ideXlab platform.
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ecosystem processes land cover climate and human settlement shape dynamic distributions for Golden Eagle across the western us
Animal Conservation, 2020Co-Authors: Jason D Tack, Barry R Noon, Zachary H Bowen, Brad C FedyAbstract:Species–environment relationships for highly mobile species outside of the breeding season are often highly dynamic in response to the collective effects of ever‐changing climatic conditions, food resources, and anthropogenic disturbance. Capturing dynamic space‐use patterns in a model‐based framework is critical as model inference often drives place‐based conservation planning. We applied dynamic occupancy models to broad‐scale Golden Eagle Aquila chrysaetos survey data collected annually from 2006 to 2012 during the late summer post‐fledging period in the western US. We defined survey sites as 10 km transect segments with a 1 km buffer on either transect side (n = 3540). Derived estimates of occupancy were low (4.4–7.9%) and turnover rates – the probability that occupied sites were newly occupied – were high (88–94%), demonstrating that annual transiency in occupancy dominates late summer behavior for Golden Eagles. Despite low philopatry during late summer, variation in Golden Eagle occupancy could be explained by a suite of land cover and annual‐varying covariates including gross primary productivity, drought severity, and human disturbance. Our summary of 13 years of predicted occupancy by Golden Eagles across the western United States identified areas that are consistently used and that may contribute significantly to Golden Eagle conservation. Restricting development and targeting mitigation efforts in these areas offers practitioners a framework for conservation prioritization.
Michael N Kochert - One of the best experts on this subject based on the ideXlab platform.
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effects of nest exposure and spring temperatures on Golden Eagle brood survival an opportunity for mitigation
Journal of Raptor Research, 2019Co-Authors: Michael N Kochert, Karen Steenhof, Jessi L BrownAbstract:We examined Golden Eagle (Aquila chrysaetos) brood survival in relation to spring temperatures and exposure of nests to afternoon sun in southwestern Idaho from 1970 through 2012. Most (77%) nests classified as shaded in a subset of 96 nests had northwest to east aspects, and most (71%) nests classified as exposed had south to west aspects. We analyzed survival of 1154 Golden Eagle broods in 64 territories. Golden Eagle brood survival at shaded and exposed nests did not differ when the daily maximum temperature was <32.2°C. Survival in exposed nests declined as the number of days with maximum temperature ≥32.2°C increased, but survival in shaded nests did not change. All broods survived from hatching to fledging age in eight exposed nests with artificial shade structures installed over a 6-yr period. During the same period, 7 of 42 broods in nests without shade structures failed to reach fledging age, with two failures (29%) attributed to thermal stress. Use of artificial shade structures in exposed nests may reduce or prevent mortality caused by heat stress, and thus might be a potential tool for mitigation of “take” from anthropogenic structures and activities. Additional experimentation under an adaptive management framework could provide more information about the effectiveness of using shade structures to offset nestling mortality associated with increasing temperatures predicted by climate change models.
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prevalence and risk factors of trichomonas gallinae and trichomonosis in Golden Eagle aquila chrysaetos nestlings in western north america
Journal of Wildlife Diseases, 2018Co-Authors: Benjamin M Dudek, Kathryn E. Purple, Michael N Kochert, Richard W. Gerhold, Joseph G Barnes, Peter H Bloom, Joseph M Papp, Kenneth V Jacobson, Charles R Preston, Chris R VennumAbstract:Abstract Avian trichomonosis, caused by the protozoan Trichomonas gallinae, affects bird-eating raptors worldwide. Raptors can develop trichomonosis by feeding on infected prey, particularly Rock Pigeons (Columba livia), which are a reservoir for T. gallinae. Raptors may be particularly vulnerable to T. gallinae infection in degraded habitats, where changes in resources may cause raptors to switch from foraging on native prey to synanthropic avian species such as Rock Pigeons. Golden Eagles (Aquila chrysaetos) typically forage on mammals; however, habitat across much of their range is experiencing degradation through changes in land use, climate, and human encroachment. In 2015, we examined the prevalence of T. gallinae infection in Golden Eagle nestlings across western North America and conducted an intensive study on factors associated with T. gallinae infection and trichomonosis in southwestern Idaho. We found T. gallinae infection in 13% (12/96) of Eagle nestlings across 10 western states and in 41% (...
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spatial and temporal patterns in Golden Eagle diets in the western united states with implications for conservation planning
Journal of Raptor Research, 2017Co-Authors: Geoffrey Bedrosian, Michael N Kochert, Karen Steenhof, Charles R Preston, James W Watson, Brian Woodbridge, Gary E Williams, Kent R Keller, Ross H CrandallAbstract:Abstract Detailed information on diets and predatory ecology of Golden Eagles (Aquila chrysaetos) is essential to prioritize prey species management and to develop landscape-specific conservation strategies, including mitigation of the effects of energy development across the western United States. We compiled published and unpublished data on Golden Eagle diets to (1) summarize available information on Golden Eagle diets in the western U.S., (2) compare diets among biogeographic provinces, and (3) discuss implications for conservation planning and future research. We analyzed 35 studies conducted during the breeding season at 45 locations from 1940–2015. Golden Eagle diet differed among western ecosystems. Lower dietary breadth was associated with desert and shrub-steppe ecosystems and higher breadth with mountain ranges and the Columbia Plateau. Correlations suggest that percentage of leporids in the diet is the factor driving overall diversity of prey and percentage of other prey groups in the diet of ...
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coming to terms about describing Golden Eagle reproduction
Journal of Raptor Research, 2017Co-Authors: Karen Steenhof, Michael N Kochert, Carol L Mcintyre, Jessi L BrownAbstract:Abstract Clearly defined terms are essential for reporting and understanding research findings, and inconsistent terminology can complicate efforts to compare findings from different studies. In this article, we reiterate and clarify recommended terms for describing Golden Eagle (Aquila chrysaetos) territory occupancy and reproduction. Several authors have provided recommendations for reporting data on raptor reproduction, but our literature review showed that authors continue to use different, often ambiguous and undefined, terms. The inconsistent use of terminology by researchers has been continued and expanded by lawmakers, regulators, and managers, perpetuating confusion. We recommend that authors clearly define and reference all terminology that they use, and we caution against use of the term “active” to describe a nest or nesting territory, because it is tainted with a history of inconsistent use. We provide a glossary of recommended terms for Golden Eagles and other large, long-lived raptors.
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effects of fire on Golden Eagle territory occupancy and reproductive success
Journal of Wildlife Management, 1999Co-Authors: Michael N Kochert, Karen Steenhof, Leslie B Carpenter, John M MarzluffAbstract:We examined effects of fire on Golden Eagle (Aquila chrysaetos) territory occupancy and reproductive success in southwestern Idaho because wildfires since 1980 have resulted in large-scale losses of shrub habitat in the Snake River Plain. Success (percentage of pairs that raised young) at burned territories declined after major fires (P = 0.004). Pairs in burned areas that could expand into adjacent vacant territories were as successful as pairs in unburned territories and more successful than pairs in burned territories that could not expand. Success at extensively burned territories was lowest 4-6 years after burning but increased 4-5 years later. The incidence and extent of fires did not help predict territories that would have low occupancy and success rates in postburn years. The presence of a vacant neighboring territory and the amount of agriculture and proportion of shrubs within 3 km of the nesting centroid best predicted probability of territory occupancy. Nesting success during preburn years best predicted the probability of a territory being successful in postburn years. Burned territories with high success rates during preburn years continued to have high success rates during postburn years, and those with low success in prebum years continued to be less successful after burning. In areas where much shrub habitat has been lost to fire, management for Golden Eagles should include active fire suppression and rehabilitation of burned areas.
Karen Steenhof - One of the best experts on this subject based on the ideXlab platform.
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effects of nest exposure and spring temperatures on Golden Eagle brood survival an opportunity for mitigation
Journal of Raptor Research, 2019Co-Authors: Michael N Kochert, Karen Steenhof, Jessi L BrownAbstract:We examined Golden Eagle (Aquila chrysaetos) brood survival in relation to spring temperatures and exposure of nests to afternoon sun in southwestern Idaho from 1970 through 2012. Most (77%) nests classified as shaded in a subset of 96 nests had northwest to east aspects, and most (71%) nests classified as exposed had south to west aspects. We analyzed survival of 1154 Golden Eagle broods in 64 territories. Golden Eagle brood survival at shaded and exposed nests did not differ when the daily maximum temperature was <32.2°C. Survival in exposed nests declined as the number of days with maximum temperature ≥32.2°C increased, but survival in shaded nests did not change. All broods survived from hatching to fledging age in eight exposed nests with artificial shade structures installed over a 6-yr period. During the same period, 7 of 42 broods in nests without shade structures failed to reach fledging age, with two failures (29%) attributed to thermal stress. Use of artificial shade structures in exposed nests may reduce or prevent mortality caused by heat stress, and thus might be a potential tool for mitigation of “take” from anthropogenic structures and activities. Additional experimentation under an adaptive management framework could provide more information about the effectiveness of using shade structures to offset nestling mortality associated with increasing temperatures predicted by climate change models.
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spatial and temporal patterns in Golden Eagle diets in the western united states with implications for conservation planning
Journal of Raptor Research, 2017Co-Authors: Geoffrey Bedrosian, Michael N Kochert, Karen Steenhof, Charles R Preston, James W Watson, Brian Woodbridge, Gary E Williams, Kent R Keller, Ross H CrandallAbstract:Abstract Detailed information on diets and predatory ecology of Golden Eagles (Aquila chrysaetos) is essential to prioritize prey species management and to develop landscape-specific conservation strategies, including mitigation of the effects of energy development across the western United States. We compiled published and unpublished data on Golden Eagle diets to (1) summarize available information on Golden Eagle diets in the western U.S., (2) compare diets among biogeographic provinces, and (3) discuss implications for conservation planning and future research. We analyzed 35 studies conducted during the breeding season at 45 locations from 1940–2015. Golden Eagle diet differed among western ecosystems. Lower dietary breadth was associated with desert and shrub-steppe ecosystems and higher breadth with mountain ranges and the Columbia Plateau. Correlations suggest that percentage of leporids in the diet is the factor driving overall diversity of prey and percentage of other prey groups in the diet of ...
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coming to terms about describing Golden Eagle reproduction
Journal of Raptor Research, 2017Co-Authors: Karen Steenhof, Michael N Kochert, Carol L Mcintyre, Jessi L BrownAbstract:Abstract Clearly defined terms are essential for reporting and understanding research findings, and inconsistent terminology can complicate efforts to compare findings from different studies. In this article, we reiterate and clarify recommended terms for describing Golden Eagle (Aquila chrysaetos) territory occupancy and reproduction. Several authors have provided recommendations for reporting data on raptor reproduction, but our literature review showed that authors continue to use different, often ambiguous and undefined, terms. The inconsistent use of terminology by researchers has been continued and expanded by lawmakers, regulators, and managers, perpetuating confusion. We recommend that authors clearly define and reference all terminology that they use, and we caution against use of the term “active” to describe a nest or nesting territory, because it is tainted with a history of inconsistent use. We provide a glossary of recommended terms for Golden Eagles and other large, long-lived raptors.
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effects of fire on Golden Eagle territory occupancy and reproductive success
Journal of Wildlife Management, 1999Co-Authors: Michael N Kochert, Karen Steenhof, Leslie B Carpenter, John M MarzluffAbstract:We examined effects of fire on Golden Eagle (Aquila chrysaetos) territory occupancy and reproductive success in southwestern Idaho because wildfires since 1980 have resulted in large-scale losses of shrub habitat in the Snake River Plain. Success (percentage of pairs that raised young) at burned territories declined after major fires (P = 0.004). Pairs in burned areas that could expand into adjacent vacant territories were as successful as pairs in unburned territories and more successful than pairs in burned territories that could not expand. Success at extensively burned territories was lowest 4-6 years after burning but increased 4-5 years later. The incidence and extent of fires did not help predict territories that would have low occupancy and success rates in postburn years. The presence of a vacant neighboring territory and the amount of agriculture and proportion of shrubs within 3 km of the nesting centroid best predicted probability of territory occupancy. Nesting success during preburn years best predicted the probability of a territory being successful in postburn years. Burned territories with high success rates during preburn years continued to have high success rates during postburn years, and those with low success in prebum years continued to be less successful after burning. In areas where much shrub habitat has been lost to fire, management for Golden Eagles should include active fire suppression and rehabilitation of burned areas.
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interactive effects of prey and weather on Golden Eagle reproduction
Journal of Animal Ecology, 1997Co-Authors: Karen Steenhof, Michael N Kochert, Trent L McdonaldAbstract:1. The reproduction of the Golden Eagle Aquila chrysaetos was studied in southwestern Idaho for 23 years, and the relationship between Eagle reproduction and jackrabbit Lepus californicus abundance, weather factors, and their interactions, was modelled using general linear models. Backward elimination procedures were used to arrive at parsimonious models. 2. The number of Golden Eagle pairs occupying nesting territories each year showed a significant decline through time that was unrelated to either annual rabbit abundance or winter severity. However, Eagle hatching dates were significantly related to both winter severity and jackrabbit abundance. Eagles hatched earlier when jackrabbits were abundant, and they hatched later after severe winters. 3. Jackrabbit abundance influenced the proportion of pairs that laid eggs, the proportion of pairs that were successful, mean brood size at fledging, and the number of young fledged per pair. Weather interacted with prey to influence Eagle reproductive rates. 4. Both jackrabbit abundance and winter severity were important in predicting the percentage of Eagle pairs that laid eggs. Percentage laying was related positively to jackrabbit abundance and inversely related to winter severity. 5. The variables most useful in predicting percentage of laying pairs successful were rabbit abundance and the number of extremely hot days during brood-rearing. The number of hot days and rabbit abundance were also significant in a model predicting Eagle brood size at fledging. Both success and brood size were positively related to jackrabbit abundance and inversely related to the frequency of hot days in spring. 6. Eagle reproduction was limited by rabbit abundance during approximately two-thirds of the years studied. Weather influenced how severely Eagle reproduction declined in those years. 7. This study demonstrates that prey and weather can interact to limit a large raptor population's productivity. Smaller raptors could be affected more strongly, especially in colder or wetter climates.