James F. Dwyer

The Journal of Raptor Research publishes the biology and conservation of diurnal and nocturnal raptors, such as their ecology, behavior, and conservation.

Electrocutions on overhead 6–10 kV electric distribution systems are killing substantial numbers of raptors in Kazakhstan, Russia, and adjacent countries. Electrocutions can also create disruptive electrical faults and outages, damage equipment, and occasionally ignite wildfires. To manage raptor electrocution risks, electric utilities in the region install Bird Protection Devices (BPDs) designed to prevent birds from contacting energized components. When installed correctly, BPDs can be highly effective. When installed incorrectly, however, electrocutions may continue to occur on retrofitted pylons. BPDs deployed beyond their intended service life may also allow electrocutions to resume. We provide examples of correctly and incorrectly installed BPDs to help readers identify five categories of retrofitting errors: product design errors, mitigation plan errors, application errors, improvisation errors, and beyond service life failures. Missteps can be avoided through carefully selecting which BPDs will be used, ensuring all risk points on a pylon are covered with BPDs, training field personnel to install BPDs correctly, ensuring BPDs are available to field personnel, communicating with manufacturers to improve BPD designs when necessary, and replacing BPDs as they approach the end of their intended service life. Electric utilities should also consider environmental stresses that may impact the effectiveness and lifespan of BPDs. The Institute of Electrical and Electronics Engineers (IEEE) recommends a sequence of tests for BPDs to ensure long-term durability, enabling electric utilities to select objectively evaluated high-quality covers. Careful attention to preventing errors and accounting for service life can help electric utilities maximize the conservation and reliability benefits of BPDs.

Summary: Collisions with powerlines affect birds worldwide, including countries such as Belgium where a nationwide model indicated high avian collision risk in the IJzerbroeken region (seasonally flooded riverside wetlands). Large numbers of waterbirds winter in this area, which is crossed by a 70-kV transmission line. To manage avian collision risk, the transmission system operator, Elia, installed AB Hammarprodukter’s FireFly™ FF line markers incorporating reflective, glow-in-the-dark, high contrast, and moving elements intended to increase the visibility of the transmission line to flying birds. We evaluated the effectiveness of FireFly line markers by comparing the numbers of avian carcasses found during 11 surveys annually in 2001 and 2018 (22 total surveys) before line markers were installed compared with 11 surveys conducted in 2021 after line marking. Before line marking, we found 30 avian carcasses attributable to collision in 2001 and 113 in 2018. After, we found six carcasses attributable to collision in 2021. In 2021, FireFly line markers correlated with a reduction in collision rate, depending on the pre-treatment year and species group, of at least 85% and up to 100%. The line was composed of two configurations, with half of the spans (two-thirds of the monitored line length) supported by tall pylons with shield wires, and half of the spans supported by shorter pylons without shield wires. After line marking, six collisions (100% in 2021) occurred on spans supported by tall pylons, and none (0%) occurred on spans supported by short pylons. Thus, in 2021, FireFly line markers correlated with an observed mortality reduction of at least 73% and up to 100%, depending on the configuration being considered. These findings suggest FireFly line markers substantially reduced wintering bird collisions in our study area.

Electrical faults caused by power escaping electric systems can lead to power outages, equipment damage, and fires. Faults sometimes occur when birds perched on power structures are electrocuted. Distribution power lines supported by concrete and steel pylons are particularly fault-prone because small separations between conductors and grounded components allow even small birds to inadvertently create faults while being electrocuted. Most conservation solutions focus on covering energized wires and components to prevent contact by birds and, although usually effective when installed correctly, covers can sometimes be dislodged thus becoming ineffective. Glass Flake Epoxy (GFE) is a non-conductive thermoset plastic that can adhere to steel crossarms and not be dislodged. We hypothesized that GFE-coated crossarms might reduce faults (proxies for avian electrocutions), and we conducted laboratory and field trials to evaluate that hypothesis. In the laboratory, we found a 2000 micrometer (μm)-thick layer of GFE coating that created a dielectric strength of 12.30 ± 0.21 kV, which was sufficient to prevent the formation of a phase-to-ground fault on up to 20 kV distribution lines. This should allow birds to perch on metal crossarms without being electrocuted. In field trials, we substituted 24% of a 20 kV distribution pylon’s crossarms with GFE-treated crossarms and found that doing so correlated with a 28% decrease in faults. Although we did not measure avian electrocutions directly, our findings suggest GFE coatings may offer a novel method of reducing avian electrocutions on power lines.

The Journal of Raptor Research publishes the biology and conservation of diurnal and nocturnal raptors, such as their ecology, behavior, and conservation.

Las áreas de distribución de muchas poblaciones de rapaces están cambiando, presumiblemente en respuesta a los efectos antropogénicos directos e indirectos en sus hábitats. La evidencia anecdótica sugiere cambios en las distribuciones de Caracara plancus a lo largo del tiempo en su área de distribución en los Estados Unidos (EEUU), aunque falta un análisis formal. En este estudio utilizamos 30 años de datos del Conteo Nacional de Aves de Navidad de la Sociedad Audubon y del Censo de Aves Reproductoras del Servicio Geológico de EEUU, divididos en diez periodos consecutivos de 3 años, para evaluar cambios y expansiones en el rango poblacional de C. plancus en Arizona, Texas y Florida, EEUU, desde 1992 hasta 2021. Los datos fueron insuficientes para evaluar la población de Arizona. En cambio, las observaciones de C. plancus aumentaron con el tiempo en Texas, donde el centroide del área de distribución se desplazó 72,6 km al norte-noreste y la población se expandió hacia Luisiana. Las observaciones de C. plancus también aumentaron con el tiempo en Florida, donde el centroide del área de distribución se desplazó 34,3 km al suroeste. Sugerimos cinco hipótesis alternativas no excluyentes para estos cambios: (1) los aumentos de temperatura debido al cambio climático podrían haber permitido una expansión reproductiva en América del Norte de esta especie principalmente sudamericana, (2) el aumento en la abundancia y en el uso de sustratos de anidación antropogénicos podría haber permitido la expansión de las poblaciones de C. plancus, (3) las mayores oportunidades de alimentación asociadas con cambios en el paisaje antropogénico podrían haber liberado a las poblaciones de C. plancus que de otra manera estarían limitadas, (4) la reducción de la persecución podría haber permitido que esta especie de comportamiento adaptable coexista en proximidad a las poblaciones humanas, y (5) la saturación del hábitat podría haber forzado una mayor dispersión. Se necesitan investigaciones futuras para evaluar y comparar estas hipótesis. [Traducción del equipo editorial]

We conducted a population genomic study of the crested caracara (Caracara plancus) using samples (n = 290) collected from individuals in Florida, Texas, and Arizona, United States. Crested caracaras are non-migratory raptors ranging from the southern tip of South America to the southern United States, including a federally protected relict population in Florida long thought to have been isolated since the last ice age. Our objectives were to evaluate genetic diversity and population structure of Florida’s apparently isolated population and to evaluate taxonomic relationships of crested caracaras at the northern edge of their range. Using DNA purified from blood samples, we conducted double-digest restriction site associated DNA sequencing and sequenced the mitochondrial ND2 gene. Analyses of population structure using over 9,000 SNPs suggest that two major clusters are best supported, one cluster including only Florida individuals and the other cluster including Arizona and Texas individuals. Both SNPs and mitochondrial haplotypes reveal the Florida population to be highly differentiated genetically from Arizona and Texas populations, whereas, Arizona and Texas populations are moderately differentiated from each other. The Florida population’s mitochondrial haplotypes form a separate monophyletic group, while Arizona and Texas populations share mitochondrial haplotypes. Results of this study provide substantial genetic evidence that Florida’s crested caracaras have experienced long-term isolation from caracaras in Arizona and Texas and thus, represent a distinct evolutionary lineage possibly warranting distinction as an Evolutionarily Significant Unit (ESU) or subspecies. This study will inform conservation strategies focused on long-term survival of Florida’s distinct, panmictic population.

Coyotes Canis latrans in urban landscapes provide important food web functions and ecological services but can also trigger human‐wildlife conflict when their diet includes anthropogenic resources or domestic pets. As adaptable omnivores, coyotes adjust their diet to their environment, routinely switching among food items to accommodate spatial and seasonal differences in availability. To evaluate the coyote's potential impacts within the food web of urban Long Beach, California where human‐wildlife conflict involving coyotes may occur, we analyzed 115 scat samples collected once every two weeks from four open space fragments inside the urban matrix. We hypothesized that differences in scat composition would correlate with seasonal and site differences, with greater use of anthropogenic resources during the dry season supplementing lower prey availability, and with greater consumption of wild mammal prey during the wet season when fruiting plants are less abundant. We found coyote diet was predominately composed of natural prey and vegetation year‐round, with seasonal variation. Mammals made up more of coyote diet in the wet season than the dry, while invertebrates and vegetation were more prevalent in dry season scats. Coyotes relied on rabbits as their main prey year‐round across all sites. Domestic cats Felis catus were the third most common individual prey species found in coyote scats, occurring in 14% of scat samples in both seasons. Coyotes also supplemented seasonally available natural food sources with anthropogenic resources, which occurred in 13% of coyote scats overall with no significant seasonal variation. While rabbits appeared in scat from all sites, the occurrence of invertebrates, small mammals, and vegetation in scats varied between sites. While there is a potential for human‐wildlife conflict in coyote's consumption of feral or domestic cats, coyotes may also be providing an ecological service by reducing cats in natural habitat fragments.

Смягчение последствий поражения электрическим током часто является первым шагом, который предпринимают операторы электросетей для снижения смертности пернатых хищников на воздушных линиях электропередачи (ВЛЭП).

Las electrocuciones en tendidos eléctricos afectan negativamente a las poblaciones de aves en los seis continentes. Las especies afectadas y las estrategias de mitigación para minimizar estos efectos están bien descritas en Norteamérica, Europa y el sur de África, y se están desarrollando en Asia, Australia y Sudamérica. Probablemente, la red eléctrica más dispersa geográficamente en el mundo se encuentra en Rusia, el país más grande del planeta, donde se han documentado electrocuciones de aves desde la década de 1970. La investigación sobre las electrocuciones de aves en Kazajistán y Rusia es extensa, pero se desconoce en gran medida fuera de Rusia, lo que limita las oportunidades de tener en cuenta los efectos regionales acumulativos. Esta revisión resume la información existente sobre las electrocuciones de aves en Kazajistán y Rusia. Las electrocuciones de aves en las líneas eléctricas se identificaron por primera vez en Rusia en 1937, ocasionando preocupación sobre el impacto en el funcionamiento de la red eléctrica, no sobre su impacto sobre las poblaciones de fauna. Los impactos aumentaron sustancialmente en la década de 1970, cuando se dejaron de utilizar apoyos con crucetas y postes de madera, con un riesgo relativamente bajo, pasando a utilizar apoyos de hormigón con crucetas de acero, que suponían, y siguen suponiendo, un riesgo mucho mayor. Los impactos sobre las poblaciones de aves rapaces son mayores donde los sistemas eléctricos de 6-10 kV atraviesan vastos paisajes áridos con pocos posaderos naturales. Las aves que se posan en los postes pueden entrar en contacto simultáneamente con conductores energizados y crucetas conectadas a tierra, creando un circuito eléctrico. Las rapaces se electrocutan con mayor frecuencia y sus electrocuciones están contribuyendo a la disminución de las poblaciones de rapaces asiáticas. Por ejemplo, las poblaciones de águila de estepa Aquila nipalensis se han desplomado en las estepas del Caspio en Kazajistán, Rusia y Ucrania, pasando de 20.000 parejas a 1.100. Las sanciones por electrocución tipificadas en la legislación rusa pretenden persuadir a las empresas eléctricas para que apliquen medidas de mitigación, pero como rara vez se aplican ni en Rusia ni en los países vecinos, las medidas de mitigación rara vez se llevan a cabo, incluso en las nuevas construcciones y en lugares con una amplia documentación de muertes por electrocución. Es importante destacar que los sistemas eléctricos son similares en los numerosos países de la antigua Unión Soviética que ahora comparten fronteras internacionales y sistemas eléctricos conectados, lo que muy probablemente plantea riesgos acumulativos sustanciales para las aves migratorias que atraviesan la región. —Dwyer, J.F., Karyakin, I.V., Garrido López, J.R. y Nikolenko, E.G. (2023). Electrocuciones de aves en tendidos eléctricos en Kazajistán y Rusia. Ardeola, 70: 3-27.