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Knowledge of mortality factors affecting raptors is often based on opportunistically found carcasses. Some causes of mortality, however, are more likely to produce carcasses that will be discovered, thus opportunistic collections are biased. Studies of raptors tagged with transmitters can provide relatively unbiased cause-of-death information. We used data collected during 2011–2021 from 158 tagged female Cooper's Hawks (Accipiter cooperii) from an urban study area in New Mexico, USA to estimate the population-level effects of different causes of mortality. We used a multistate model to combine data from encounters of banded live and dead birds with data from transmitter-tagged hawks to estimate annual age-specific survival rates. Cause-of-death information from the subset of tagged individuals was used to estimate proportions of first year (FY) and older (AFY) hawks that died annually from different causes. Most mortalities were caused by anthropogenic factors, especially collisions with human structures (e.g., windows, vehicles), which accounted for 45% (credible interval = 31%–60%) of FY deaths and 32% (18%–45%) of AFY deaths annually. From July 2020 to June 2021, purposeful killing by humans accounted for deaths of 17 (6–33) female Cooper's Hawks out of an estimated starting population of 216 (184–254). For both age classes, the ultimate cause of most deaths in late winter and early spring appeared to be associated with securing a nesting territory and mate. To our knowledge, this is the first study to provide relatively unbiased information on the importance of different causes of mortality for an urban raptor population. El conocimiento de los factores de mortalidad que afectan a las aves rapaces a menudo se basa en cadáveres encontrados de manera oportunista. Sin embargo, algunas causas de mortalidad son más propensas a producir cadáveres que serán descubiertos, por lo que las recolecciones oportunistas están sesgadas. Los estudios de rapaces seguidas con transmisores pueden proporcionar información relativamente imparcial sobre las causas de mortalidad. Utilizamos datos recolectados durante 2011–2021 de 158 hembras de Accipiter cooperii provenientes de un área de estudio urbana en Nuevo México, EEUU, para estimar los efectos a nivel poblacional de diferentes causas de mortalidad. Utilizamos un modelo de múltiples estados para combinar los datos de encuentros de aves anilladas vivas y muertas con los datos de aves seguidas por medio de transmisores para estimar tasas anuales de supervivencia específicas por edad. La información sobre la causa de mortalidad del subconjunto de individuos marcados con transmisores se utilizó para estimar las proporciones de A. cooperii del primer año (PA) y post primer año (PPA) que murieron anualmente por diferentes causas. La mayoría de las muertes fueron causadas por factores antropogénicos, especialmente colisiones con estructuras humanas (e.g., ventanas, vehículos), que representaron, anualmente, el 45% (31%–60%) de las muertes de PA y el 32% (18%–45%) de las muertes de PPA. Desde julio de 2020 a junio de 2021, la muerte intencional por parte de humanos representó la muerte de 17 (6–33) hembras de A. cooperii de una población inicial estimada en 216 (184–254) individuos. Para ambas clases de edad, la causa última de la mayoría de las muertes a fines del invierno y principios de la primavera pareció estar asociada con asegurar un territorio de nidificación y una pareja. Hasta donde sabemos, este es el primer estudio que proporciona información relativamente no sesgada sobre la importancia de diferentes causas de mortalidad para una población urbana de aves rapaces. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]

Much of the US Southern Great Plains (SGP) continues to undergo intensive energy development that could affect the region's Golden Eagles (Aquila chrysaetos), yet the species' population status there is unknown. During 2011–2020, we used satellite telemetry to assess annual survival rates and causes of mortality among 40 preadult (<3 yr of age) Golden Eagles in the SGP; 29 were monitored beginning at the late nestling stage and 11 immigrated into the SGP from western regions. For comparison we monitored 15 preadult Golden Eagles from nests in the Central Great Plains (CGP), where energy development was less extensive. We estimated survival rates by using a multi-state model in a Bayesian framework that accounted for probabilities of causes of death. Mean annual survival in the SGP during the preadult period was 0.060, versus 0.512 in the CGP and ∼0.7–0.9 reported elsewhere in the coterminous western USA. Mexican chicken bugs (Haematosiphon inodorus) were implicated in deaths of at least seven Golden Eagles during the ∼2-wk late nestling stage and in two deaths <3 mo after fledging. Energy infrastructure especially electrocutions accounted for 12 (57.1%) of 21 deaths of post-fledged preadults. Seven of 11 immigrant eagles died. Overall, probabilities of death of a Golden Eagle during the preadult period in the SGP due to Mexican chicken bugs and to electrocution were both 0.345. We estimated that the SGP population may be declining 9% annually due to poor recruitment; mitigation of underlying factors should be a priority for managing Golden Eagles in the western USA. Buena parte de las Grandes Llanuras del Sur (GLS) de EEUU continúan sometidas a un desarrollo energético intensivo que podría afectar a los individuos de Aquila chrysaetos de la región; sin embargo, el estado de la población de la especie en esta zona es desconocido. Durante 2011–2020, usamos telemetría satelital para evaluar las tasas de supervivencia anuales y las causas de mortalidad entre 40 águilas preadultas (<3 años de edad) de A. chrysaetos en las GLS; 29 fueron monitoreadas a partir de la etapa tardía de polluelo y 11 inmigraron desde regiones del oeste. Para hacer una comparación, monitoreamos 15 águilas preadultas de A. chrysaetos en nidos de las Grandes Llanuras Centrales (GLC), donde el desarrollo energético era menos extenso. Estimamos las tasas de supervivencia utilizando un modelo multi-estado en un marco de trabajo bayesiano que tuvo en cuenta las probabilidades de las causas de muerte. La supervivencia media anual en las GLS durante el periodo preadulto fue de 0.060, en comparación con 0.512 en las GLC y ∼0.7–0.9 en otras partes del oeste contiguo de EEUU. La chinche Haematosiphon inodorus estuvo implicada en la muerte de al menos siete águilas durante las últimas ∼2 semanas de la etapa tardía de polluelo y en dos muertes durante el inicio del postemplumamiento. La infraestructura energética, especialmente las electrocuciones, representaron 12 (57.1%) de las 21 muertes de preadultos después de emplumar. Siete de las 11 águilas inmigrantes murieron. En general, las probabilidades de muerte de un individuo de A. chrysaetos durante el período preadulto en las GLS debido a las chinches y a la electrocución fueron ambas de 0.345. Estimamos que la población de las GLS puede estar disminuyendo un 9% anual debido al bajo reclutamiento; la mitigación de los factores subyacentes debería ser una prioridad para la gestión de A. chrysaetos en el oeste de EEUU. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]

Deaths of four Golden Eagles (Aquila chrysaetos) due to collision trauma at a new wind energy facility in east-central New Mexico during 2004–2005 prompted concerns about the species' population status in the encompassing Southern Great Plains region, primarily because its breeding distribution there was poorly documented and wind energy development was expanding rapidly. Therefore, we conducted aerial searches for Golden Eagle nests across northeastern New Mexico, northwestern Texas, western Oklahoma, and adjacent portions of Colorado and Kansas during 2006–2009 and 2015–2020. We delineated five Golden Eagle Nest Search Areas (NSAs) with unique physiographic/geological origins. Individual NSAs were searched partially or entirely for up to 8 yr. Collectively, we identified 123 nesting territories (NTs) occupied by Golden Eagles ≥ 1 yr, of which 94 (76%) were in northeastern New Mexico. The most NTs (40) were in the 11,720-km2 Highlands NSA. Greatest NT density (126.6 km2/NT) and shortest NT nearest neighbor distance (7.4 km) were in the 3533-km2 Northern Caprock NSA. Wind turbines existed near (within 3.2 km) eight nests distributed among five of 28 NTs in the Northern Caprock and were planned for sites in two occupied NTs. Elsewhere, only potential turbines were near nests and only within six NTs. The number of nesting territories we found underscores the importance of the Southern Great Plains to Golden Eagles, even though this region lies at the eastern margin of the species' western North American breeding range. Our data provide strong support for protecting breeding habitat from potential threats, particularly those posed by wind energy development, and are also a foundation for long-term population monitoring. La muerte de cuatro individuos de Aquila chrysaetos debido a traumatismos por colisión en una nueva instalación de energía eólica en el centro-este de Nuevo México durante 2004–2005 generó preocupación sobre el estado poblacional de la especie en la región de las Grandes Llanuras del Sur, principalmente debido a que allí su distribución reproductiva estaba mal documentada y el desarrollo de la energía eólica se estaba expandiendo rápidamente. Por lo tanto, realizamos búsquedas aéreas de nidos de A. chrysaetos en el noreste de Nuevo México, el noroeste de Texas, el oeste de Oklahoma y partes adyacentes de Colorado y Kansas durante 2006–2009 y 2015–2020. Delineamos cinco Áreas de Búsqueda de Nidos (ABN) de A. chrysaetos con orígenes fisiográficos/geológicos únicos. Las ABN individuales fueron exploradas parcial o totalmente durante un máximo de 8 años. En conjunto, identificamos 123 territorios de nidificación (TN) ocupados por ejemplares de A. chrysaetos ≥ 1 año, de los cuales 94 (76%) se encontraron en el noreste de Nuevo México. La mayoría de los TN (40) se encontraron en el ABN de Highlands, con una superficie de 11.720 km2. La mayor densidad de TN (126.6 km2/TN) y la menor distancia al TN del vecino más cercano (7.4 km) se encontraron en el ABN de Northern Caprock, de 3533 km2. Hubo presencia de parques eólicos cerca (dentro de los 3.2 km) de 8 nidos distribuidos en cinco de los 28 TN en Northern Caprock, y otros parques fueron planificados para lugares cercanos a dos TN ocupados. En otras partes, solo parques eólicos potenciales estuvieron cerca de los nidos y sólo seis dentro de TN. La cantidad de territorios de nidificación que encontramos subraya la importancia de las Grandes Llanuras del Sur para A. chrysaetos, a pesar de que esta región se encuentra en el margen este del área de reproducción oeste de la especie en Norteamérica. Nuestros datos proporcionan un apoyo sólido para proteger el hábitat de cría de posibles amenazas, en particular de aquellas que plantea el desarrollo de la energía eólica, y también son una base para el seguimiento de la población a largo plazo. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]

The article explores The southern limit of the Golden Eagle's (Aquila chrysaetos) breeding range in North America is Mexico, where the eagle is the national symbol yet designated as a threatened, high priority species for conservation action. Movement information needed for conserving Mexico's Golden Eagles is sparse; knowledge of dispersal from natal areas is essential to understand the eagle's ecology and help provide for its management.

Copyright of Journal of Raptor Research is the property of Raptor Research Foundation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Electrocution on overhead electric systems is a primary cause of anthropogenic mortality for Golden Eagles (Aquila chrysaetos) in North America. Distribution poles supporting energized equipment are most often involved in electrocutions, but the frequency with which Golden Eagles perch on pole supporting equipment is unknown. To resolve questions of perch frequency, and by extension, electrocution risk and mitigation prioritization, we used Google Earth to identify perch locations of GPS-transmittered preadult Golden Eagles, and specifically to identify perching on poles supporting transformers. We used transformer poles as a proxy for electrocution risk because transformers are visible in Google Earth imagery. We examined 105 randomly selected "perch events" for each of 10 Golden Eagles (n = 1050 perch events total) tracked for a mean of 16 consecutive mo after fledging. The most frequently used perch sites were cliffs (24.6%), trees (21.2%), and hills (16.6%). Across individuals, 10.8% of perches were on overhead electric systems (individual ranges = 0.0–34.3%). Seven Golden Eagles perched on a distribution pole at least once. Of these, five perched on a transformer pole at least once. Perching on transformer poles occurred more frequently than expected given the proportion of transformer poles present (Yates' χ2 = 26.5, P < 0.001). Given the frequency of perching on transformer poles revealed in this study and the frequency of electrocution on equipment poles revealed in previous studies, the data suggest that electrocution mitigation measures should be focused on equipment poles. Future research should quantify perching across a wider variety of habitats and Golden Eagle age and sex to identify whether the patterns reported here occur more broadly. [ABSTRACT FROM AUTHOR]

Knowledge of dispersal from natal areas by pre-breeding-age Golden Eagles ( Aquila chrysaetos) in North America is sparse, though crucial for conservation planning. During 2010-2015, we used satellite telemetry to document movement behavior of pre-breeding-age Golden Eagles from the Colorado Plateau and Southern Rocky Mountains of the southwestern U.S.A. Here we report on (1) 1st-yr dispersal timing, distances, strategies, and survival; (2) influences of age, sex, nest-mates, and area of origin; and (3) progressive distancing from natal nests and coinciding space use, including overlap between individuals' home ranges at the end of their 1st and 2nd yr. Our dataset included 293,960 GPS fixes from 66 Golden Eagles monitored through at least the onset of dispersal. All dispersed at age <1 yr. Most (66.7%) initiated dispersal during 16 September-21 November (median = 22 October, 191 d after median hatch date). We could assign each of 60 eagles to one of four 1st-yr dispersal categories based on maximum distance traveled from natal nests: short-distance (SD), generally <120 km (66.7% of eagles); moderate-distance (MD), 120-500 km (16.7%); long-distance (LD) >500 km (13.3%); and Other (3.3%). LDs dispersed at younger ages than SDs and were more likely to be from the arid half of our study area. First-year survival was significantly lower for LDs. Overlap of 95% kernel density home ranges at ages 12 and 24 mo was 42.2% (±6.4 SE) for 26 SDs and 26.5% (±9.5) for eight MDs. Our data indicate that, during at least their 1st and 2nd yr of life, most Golden Eagles from the Colorado Plateau and Southern Rocky Mountains remain within 120 km of their nests, where they experience high survival and are relatively settled by the end of their 1st yr. As such, these landscapes are key habitat for at least 1st- and 2nd-yr eagles as well as breeding pairs. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Raptor Research is the property of Raptor Research Foundation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Raptor Research is the property of Raptor Research Foundation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article focuses on a study which summarizes documented cases of eagle mortality at wind energy facilities in the contiguous U.S., excluding Altamont Pass Wind Resource Area (APWRA), from 1997 to June 30, 2012, as starting point for future assessments. Information on eagle mortalities and injuries that occurred in the said period were retrieved using public-domain sources. Results revealed a minimum of 85 eagle mortalities at 32 wind energy facilities in 10 states during the said period.