We measured spatial use and habitat selection of radio-tagged Golden Eagles (Aquila chrysaetos) at eight to nine territories each year from 1992 to 1994 in the Snake River Birds of Prey National Conservation Area. Use of space did not vary between years or sexes, but did vary among seasons (home ranges and travel distances were larger during the nonbreeding than during the breeding season) and among individuals. Home ranges were large, ranging from 190 to 8,330 ha during the breeding season and from 1,370 to 170,000 ha outside of the breeding season, but activity was concentrated in small core areas of 30 to 1,535 ha and 485 to 6,380 ha during the breeding and nonbreeding seasons, respectively. Eagles selected shrub habitats and avoided disturbed areas, grasslands, and agriculture. This resulted in selection for habitat likely to contain their principal prey, black-tailed jackrabbits (Lepus californicus). Individuals with home ranges in extensive shrubland (n = 3) did not select for shrubs in the placement of their core areas or foraging points, but individuals in highly fragmented or dispersed shrublands (n = 5) concentrated their activities and foraged preferentially in jackrabbit habitats (i.e. areas with abundant and large shrub patches). As home ranges expanded outside of the breeding season, individuals selected jackrabbit habitats within their range. Shrubland fragmentation should be minimized so that remaining shrub patches are large enough to support jackrabbits. IN SOUTHWESTERN IDAHO, the demography and behavior of Golden Eagles (Aquila chrysaetos) are closely associated with variation in the abundance of black-tailed jackrabbits (Lepus californicus). Jackrabbit populations fluctuate, peaking at 7-to-12 year intervals (Johnson and Peek 1984). More eagles lay eggs and produce more offspring when jackrabbits are abundant than when jackrabbit populations crash (Steenhof et al. 1997), and eagles use alternative prey when jackrabbits decline (Steenhof and Kochert 1988). The importance of jackrabbits to eagles suggests that eagles should locate territories and concentrate foraging activities in habitats most likely to contain jackrabbits. We tested this hypothesis by relating spatial-use patterns of eagles to habitats associated with blacktailed jackrabbits. We then could indirectly describe habitat use by eagles relative to their main prey and quantify habitat characteristics meaningful to land managers. 3Present address: College of Forest Resources, Although descriptions of average behavior may be most easily understood by biologists and translated into management policy, they do not capture variation among individual animals. If such variation is substantial and ignored by focusing on population averages, conservation strategies and biological descriptions will be inaccurate and rarely effective. Describing individual variation, attempting to understand it, and using this to provide context-specific management recommendations would be preferable. Furthermore, many animals select and use resources at variou...

In an attempt to reduce the high extinction risk inherent to small island populations, we translocated wild Laysan teal Anas laysanensis to a portion of its presumed prehistoric range. Most avian translocations lack the strategic postrelease monitoring needed to assess early population establishment or failure. Therefore, we monitored the survival and reproduction of all founders, and their first-generation offspring using radio telemetry for 2 years after the first release. The effective founding female population (N e ) was 13. We applied these initial demographic rates to model population growth. The nascent population size increased to 4100 after only 2 years post-release (l = 1.73). If this growth rate continues, the size of the Midway population could surpass the source population before 2010.

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Understanding the behavioral ecology of species of conservation concern can help to inform better management. During winters 2011 through 2017, we placed camera traps at stations baited with carrion to investigate characteristics of winter scavenging by golden eagles (Aquila chrysaetos) and bald eagles (Haliaeetus leucocephalus) in eastern Washington and Oregon, USA. Our objectives were to better understand exposure risk of individual eagles to lead contaminants and evaluate factors that affect eagle visitation to carrion to inform measures that reduce lead exposure. We studied photo sequences from 108 traps (truex¯ = 2,725 ± 306 [SE] images/trap) and used plumage and physical characteristics to track visitation of 183 individual golden eagles and 90 bald eagles at deer (Odocoileus spp.) carrion until it was totally consumed. At least 1 eagle visited 76% of traps (truex¯ = 2.5 ± 0.3 unique eagles/trap). On average, an eagle visited a trap 3.4 ± 0.2 times (range = 1–19 visits) over 1.9 ± 0.1 days (range = 1–9 days). We used general linear mixed models to identify influences on number of eagle visits and pooled visit duration. Individual golden eagles visited carrion about 25% more often and 50% longer than bald eagles, and individual juvenile eagles visited carrion more often and longer than immature and adult eagles. On average, an eagle made an additional visit to carrion for every golden eagle that came to the same trap. Eagles spent less time at offal (truex¯ = 26.2 ± 6.4 min) than at a whole carcass (truex¯ = 92.9 ± 7.5 min), and understory vegetation immediately surrounding carrion was associated with a 30% reduction in visitation time. In the Pacific Northwest during winter, adult and juvenile golden eagles, by virtue of their abundance and visitation to carrion compared to the immature age class and bald eagles of all ages, have the highest potential for exposure to anthropogenic effects from carrion visitation. Concealment of offal piles in vegetation may reduce, but not eliminate, eagle use because of competing scavengers that expose carrion locations. We found no evidence that carrion proximity to nearest known nests, topography, or snow cover affect visitation by eagles. Thus, short of using alternative ammunition to lead, we recommend burial or removal of offal from hunter‐killed ungulates. © 2019 The Wildlife Society.