Brian A. Millsap’s research while affiliated with New Mexico State University and other places

Wind power is increasingly meeting global renewable energy demands; however, more turbines leads to increased bird-turbine collisions, particularly raptors, which can negatively impact populations. We estimated annual turbine mortalities of the federally-protected golden eagle (Aquila chrysaetos) in the western United States (2013–2024) with a Bayesian collision risk model (CRM). We used eBird relative abundance data to predict areas where golden eagles are at lower or higher risk of turbine collisions and turbine data from the U.S. Geological Survey U.S. Wind Turbine Database. From 2013 to 2024, estimated turbine hazardous volume in the lower- and higher-risk zone increased by 198 % and 119 %, respectively. Anthropogenic mortality is the primary cause of death in adult golden eagles and recent trends indicate their population may be declining. If the current rate of growth of the wind energy industry continues, it could have conservation implications for golden eagle and other raptor populations.

Disturbances, such as fire, play a significant role in shaping ecosystems worldwide, however anthropogenic pressures have modified environments and disturbance regimes, presenting unique challenges for wildlife. We investigated the response of a male Gray Hawk (Buteo plagiatus) to a wildfire event within its core territory in the Santa Ana National Wildlife Refuge in the Lower Rio Grande Valley of south Texas. Contrary to our expectations, the hawk remained within its home range throughout the fire and after the fire was extinguished, exhibiting resilience to an uncommon disturbance. Utilizing GPS tracking data, we analyzed the hawk’s movements before, during, and after the wildfire, revealing minimal changes in home range size and distribution. Our findings highlight the importance of understanding species specific responses to wildfires in increasingly altered ecosystems and underscore the need for further research to inform conservation strategies in the face of changing disturbance regimes and habitat dynamics.

As the human footprint expands to meet societal energy needs, as do the impacts to wildlife. Raptors in particular are highly susceptible to anthropogenic caused mortality. Industry sectors are encouraged to offset these causes of mortality. Several options to mitigate these losses have been proposed, including raptor rehabilitation. However, its role as a conservation tool is untested. Currently no peer‐reviewed demographic analyses exist using post‐release data from rehabilitated raptors to evaluate its effectiveness at continental scales. Our objectives were to estimate annual survival of rehabilitated and wild raptors, and then use those estimates in demographic models to assess potential effects at individual and population levels. We hypothesized that rehabilitated raptors would survive similarly to their wild counterparts after an acclimation period, and that longer‐lived species (K‐selected) would benefit most from these releases. We used US Geological Survey Bird Banding Lab band‐recovery data (1974–2018) from 20 raptor species for modeling survival of rehabilitated individuals (n = 125 740) in comparison to wild birds (n = 1 913 352). Results from 17 species with adequate recovery data indicated that five species rehabilitated ≠ wild survival, two species had uncertain estimates, and 10 species rehabilitated ≈ wild survival by years two and three post‐release. We acquired admission (n = 69 707) and release (n = 25 740) data from 24 rehabilitation centers across the US (2012–2021). We integrated survival, fecundity and numbers of releases into demographic models. These models quantified the extent to which rehabilitated raptors may contribute to broader conservation efforts, especially in the context of individual take. All but two species, had measurable numbers of individuals added to the population regardless of the number of releases. The general pattern was for K‐selected species to yield larger benefits from rehabilitated supplementation to the population. These results provide evidence that rehabilitation may serve as mitigation tool to offset incidental take.

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. KEY WORDS: mortality factors; mortality rates; multistate models; survival; urban. CAUSAS DE MORTALIDAD EN HEMBRAS DE ACCIPITER COOPERII EN UN ENTORNO URBANO DE NUEVO M EXICO, EEUU RESUMEN.-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 rela-tivamente 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 múlti-ples 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

Anthropogenic pressures on the global landscape are rapidly increasing, with well-documented negative impacts on avian populations. As an encouraging counterexample to general declines, the bald eagle Haliaeetus leucocephalus population in the United States has continued to grow dramatically since its 20th century decline, with breeding pairs now colonizing areas with high levels of human activity. Evidence of the impact of human activity on nesting bald eagles is mixed, with some studies reporting declines in reproduction, whereas others suggest that reproduction is comparatively unaffected. This study improves our understanding of bald eagle reproductive performance when exposed to human activities and will provide better guidance for managing this species.

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]

Population size is a key metric for management and policy decisions, yet wildlife monitoring programmes are often limited by the spatial and temporal scope of surveys. In these cases, citizen science data may provide complementary information at higher resolution and greater extent. We present a case study demonstrating how data from the eBird citizen science programme can be combined with regional monitoring efforts by the US Fish and Wildlife Service to produce high‐resolution estimates of golden eagle abundance. We developed a model that uses aerial survey data from the western United States to calibrate high‐resolution annual estimates of relative abundance from eBird. Using this model, we compared regional population size estimates based on the calibrated eBird information with those based on aerial survey data alone. Population size estimates based on the calibrated eBird information had strong correspondence to estimates from aerial survey data in two out of four regions, and population trajectories based on the two approaches showed high correlations. We demonstrate how the combination of citizen science data and targeted surveys can be used to (a) increase the spatial resolution of population size estimates, (b) extend the spatial extent of inference and (c) predict population size beyond the temporal period of surveys. Findings based on this case study can be used to refine policy metrics used by the US Fish and Wildlife Service and inform permitting regulations (e.g. mortality/harm associated with wind energy development). Policy implications: Our results demonstrate the ability of citizen science data to complement targeted monitoring programmes and improve the efficacy of decision frameworks that require information on population size or trajectory. After validating citizen science data against survey‐based benchmarks, agencies can harness strengths of citizen science data to supplement information needs and increase the resolution and extent of population size predictions.

Anthropogenic pressures on the global landscape are rapidly increasing, with well-documented negative impacts on avian populations. As an encouraging counterexample to general declines, the bald eagle Haliaeetus leucocephalus population in the United States has continued to grow dramatically since its 20th century decline, with breeding pairs now colonizing areas with high levels of human activity. Evidence of the impact of human activity on nesting bald eagles is mixed, with some studies reporting declines in reproduction, while others suggest reproduction is comparatively unaffected. We assessed the effects of anthropogenic activities on bald eagle nest success by compiling data from bald eagle incidental take permits issued by the U.S. Fish and Wildlife Service for unintentional disturbance of breeding bald eagles. We used generalized linear logistic regression models in a Bayesian framework to evaluate the relationship between types of human activity (n = 6), levels of human development in the environment around nests (n = 5), and whether or not the activity resulted in a significant alteration of the surrounding habitat. There were more permits issued for nests in suburban (40%) than in natural (12%) or industrial (9%) environments and nearly half (47%) of the permits were for building activities; there was a similar number of permits where the habitat was altered (46%) or unaltered (54%). Overall mean nest success during authorized activities from 103 nest-seasons was 84% (95% credible interval: 76–90%) and nest success rates were similarly high (77–100%) for all categories within covariates (p > 0.6). The top model was without fixed effects, accounting for 47% of the model set weight, and the next three models, the only other models with widely applicable information criterion weight, included the activity type and habitat alteration covariates. The only parameters with 95% credible intervals encompassing zero were infrastructure and landscape modification activities, for which all nests exposed to these activities were successful; however, these estimates also had very high uncertainty. This indicates that the covariates we tested were weak predictors of nest success. Some permitted nests were monitored prior to or following years of authorized activity, and there was no significant difference in nest success between activity and non-activity years. We provide further evidence that the growing contingent of bald eagles nesting in human-developed environments tolerate anthropogenic activities to a degree that they are able to nest successfully at rates comparable to the general U.S. population. This study improves our understanding of bald eagle reproductive performance when exposed to human activities and will provide better guidance for managing this species.

The United States is rapidly expanding production of renewable energy to meet increased energy demands and reduce greenhouse gas emissions. Wind energy is at the forefront of this transition. A central challenge is understanding the nexus between wind energy development and its capacity for negative effects on wildlife causing population declines and habitat loss. Collaboration among conservationists and developers, early in the planning process, is crucial for minimizing wind-wildlife conflicts. Such collaborations require data showing where wind and wildlife impacts occur. To meet this challenge and inform decision-making, we provide natural resource agencies and stakeholders information regarding where future wind turbines may occur, and the potential affects on natural resource management, including the conservation of priority species and their habitats. We developed a machine learning model predicting suitability of wind turbine occurrence (hereafter, wind turbine suitability) across an eight-state region in the United States, representing some of the richest areas of wind potential. Our model incorporates predictor variables related to infrastructure, land ownership, meteorology, and topography. We additionally created a constraint layer indicating areas where wind would likely not be developed because of zoning, protected lands, and restricted federal agency proximity guidelines. We demonstrate how the predictive wind turbine suitability model informs conservation planning by incorporating animal movement models, relative abundance models coupled with spatial conservation planning software, and population density models for three exemplar, high priority species often affected by wind energy: whooping cranes (Grus americana), golden eagles (Aquila chrysaetos), and lesser prairie-chickens (Tympanuchus pallidicinctus). By merging the wind turbine and biological models, we identified conservation priority areas (i.e., places sharing high suitability for wind turbines and species use), and places where wind expansion could minimally affect these species. We use our “species-wind turbine occurrence relationships” to demonstrate applications, illustrating how forecasting areas of wind turbine suitability promotes wildlife conservation. These relationships inform wind energy siting to reduce negative ecological impacts while promoting environmental and economic viability.