Patterns of Spatial Distribution of Golden Eagles Across North America: How Do They Fit into Existing Landscape-scale Mapping Systems?
Conserving wide-ranging animals requires knowledge about their year-round movements and resource use. Golden Eagles (Aquila chrysaetos) exhibit a wide range of movement patterns across North America. We combined tracking data from 571 Golden Eagles from multiple independent satellite-telemetry projects from North America to provide a comprehensive look at the magnitude and extent of these movements on a continental scale. We compared patterns of use relative to four alternative administrative and ecological mapping systems, namely Bird Conservation Regions (BCRs), U.S. administrative migratory bird flyways, Migratory Bird Joint Ventures, and Landscape Conservation Cooperatives. Our analyses suggested that eagles initially captured in eastern North America used space differently than those captured in western North America. Other groups of eagles that exhibited distinct patterns in space use included long-distance migrants from northern latitudes, and southwestern and Californian desert residents. There were also several groupings of eagles in the Intermountain West. Using this collaborative approach, we have identified large-scale movement patterns that may not have been possible with individual studies. These results will support landscape-scale conservation measures for Golden Eagles across North America. La conservación de animales de distribución amplia requiere conocer sus movimientos a lo largo del ciclo anual y su uso de recursos. Aquila chrysaetos presenta un amplio rango de patrones de movimiento a través de América del Norte. Combinamos datos de seguimiento de 571 ejemplares de A. chrysaetos de múltiples proyectos independientes de telemetría satelital de América del Norte para proporcionar un análisis completo sobre la magnitud y el alcance de estos movimientos a escala continental. Comparamos los patrones de uso en relación a cuatro sistemas de mapeo administrativos y ecológicos, específicamente las Regiones para la Conservación de Aves (RCAs), las rutas administrativas de aves migratorias de Estados Unidos, los Emprendimientos Mixtos de Aves Migratorias y las Cooperativas para la Conservación de Paisajes. Nuestros análisis sugieren que las águilas capturadas inicialmente en el este de América del Norte utilizaron el espacio de una manera diferente a las capturadas en el oeste de América del Norte. Otros grupos de águilas que exhibieron patrones distintos de uso del espacio incluyeron individuos migradores de larga distancia provenientes de latitudes septentrionales e individuos residentes de California y provenientes del sur. También hubo numerosas agrupaciones de águilas en el oeste inter-montano. Utilizando este enfoque colaborativo, identificamos patrones de movimientos a gran escala que no hubieran sido posibles a partir de estudios individuales. Estos resultados apoyan las medidas de conservación a escala de paisaje para A. chrysaetos a lo largo y ancho de América del Norte. [Traducción del equipo editorial]Abstract
Resumen

Boundaries of (A) Bird Conservation Regions (BCR), (B) Flyways, (C) Joint Ventures (JV), and (D) Landscape Conservation Cooperatives (LCC) in North America.

Telemetry fixes of 571 Golden Eagles tracked in North America between 1992 and 2016. Lines indicate unobserved straight-line paths between consecutive telemetry fixes.

Example of quality statistics for clustering solutions (x-axis indicates number of clusters) for (A) Bird Conservation Regions (BCR), (B) Flyways, (C) Joint Ventures (JV), and (D) Landscape Conservation Cooperatives (LCC). Average silhouette width is ASW, Hubert's Gamma is HG, and PBC is Point Biserial Correlation. The peak or point of inflection of each curve suggests a number of clusters that balances cluster quality with cluster number, indicated by dashed vertical lines.

Percent of Golden Eagle telemetry fixes in relation to U.S. Fish and Wildlife Service Landscape Conservation Cooperative (LCC) units within movement clusters.

Inferred paths of Golden Eagles (gray lines) overlying the number of telemetry fixes of eagles within classified movement clusters in relation to U.S. Fish and Wildlife Service Landscape Conservation Cooperative (LCC) units.

Numbers of Golden Eagles captured within geographic units for (A) Bird Conservation Regions (BCR), (B) Flyways, (C) Joint Ventures (JV), and (D) Landscape Conservation Cooperatives (LCC).
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