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Filters: Tags: Journal of Raptor Research (X) > partyWithName: Karen Steenhof (X)

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We reviewed the literature to assess status and population trends and to identify mortality factors affecting Golden Eagle populations in the U.S. and Canada. Nesting populations in Alaska and Canada are stable, but some nesting populations in the western U.S. have declined. Small but steady declines in the intermountain West have been associated with shrub loss and declining jackrabbit populations; declines in southern California have been attributed to urbanization. Migration counts in the eastern U.S. suggest a decline in Golden Eagles from the 1930s to the early 1970s, with a stable or increasing trend since the early 1970s. No significant trends in migration counts were reported for Golden Eagles in the western...
Categories: Publication; Types: Citation; Tags: Journal of Raptor Research
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Clearly defined terms are essential for reporting and understanding research findings, and inconsistent terminology can complicate efforts to compare findings from different studies. In this article, we reiterate and clarify recommended terms for describing Golden Eagle (Aquila chrysaetos) territory occupancy and reproduction. Several authors have provided recommendations for reporting data on raptor reproduction, but our literature review showed that authors continue to use different, often ambiguous and undefined, terms. The inconsistent use of terminology by researchers has been continued and expanded by lawmakers, regulators, and managers, perpetuating confusion. We recommend that authors clearly define and...
Categories: Publication; Types: Citation; Tags: Journal of Raptor Research
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http://elibrary.unm.edu/sora/jrr/v028n03/p00194-p00196.pdf
Categories: Publication; Types: Citation; Tags: Journal of Raptor Research
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Birds face challenges in how they allocate energy during the reproductive season. Most temperate zone species do not breed and molt at the same time, presumably because of the high energy demands of these two activities (Espie et al. 1996 and citations therein). However, representatives of at least four raptor genera are known to molt during the nesting season (Schmutz and Schmutz 1975, Newton and Marquiss 1982, Schmutz 1992, Espie et al. 1996). Molt strategies vary among raptor species depending on prey abundance, migration strategies, and the relative costs of reproduction. Sexually-dimorphic raptors typically have different roles in parenting, which result in different strategies for energy allocation. Male and...
Categories: Publication; Types: Citation; Tags: Journal of Raptor Research
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We studied nest use by Golden Eagles (Aquila chrysaetos) from 1966 to 2011 to assess nest reuse within territories, ascertain the length of time that elapses between uses of nests, and test the hypotheses that reproductive success and adult turnover influence nest switching. Golden Eagles used 454 nests in 66 territories and used individual nests 1 to 26 times during 45 continuous years of observation. Time between reuse ranged from 1 to 39 yr. Distances between nearest adjacent alternative nests within territories ranged between <1 and 1822 m, and distances between 90% of adjacent nests were <500 m. Of all nests used, 21% fell or disintegrated, and 31% were newly constructed during the study. Nest switching was...
Categories: Publication; Types: Citation; Tags: Journal of Raptor Research
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Thirty-nine bald eagles found sick or dead in 13 States during 1969 and 1970 were analyzed for pesticide residues. Residues of DDE, dieldrin, polychlorinated biphenyls (PCB's), and mercury were detected in all bald eagle carcasses; DDD residues were detected in 38; DDT, heptachlor epoxide, and dichlorobenzophenone (DCBP) were detected less frequently. Six eagles contained possible lethal levels of dieldrin in the brain, and one contained a lethal concentration of DDE (385 ppm) in the brain together with 235 ppm of PCB's. Autopsy revealed that 18 bald eagles were illegally shot; other causes of death were impact injuries, electrocution, emaciation, and infectious diseases.
Categories: Publication; Types: Citation; Tags: Journal of Raptor Research
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We studied Bald Eagle foraging ecology on the South Fork Boise River,Idaho, during the winters of 1990-92. We compared habitat variables at 29 foraging sites, 94 perch sites, and 131 random sites.Habitat variables included river habitat (pool, riffle, run), distance to the nearest change in river habitat, distance to nearest available perch, number and species of surrounding perches, and average river depth and flow. Eagles foraged more at pools than expected, and closer( (15 m) to changes in river habitat than expected. Where eagles foraged at riffles, those riffles were slower than riffles where they perched or riffles that were available at random. Where eagles foraged at runs, those runs were shallower than...
Categories: Publication; Types: Citation; Tags: Journal of Raptor Research
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We studied Prairie Falcon (Falco mexicanus) breeding dispersal, natal dispersal, and turnover at nesting areas in the Snake River Birds of Prey National Conservation Area (NCA) from 1971- 95. Of 61 nesting areas where falcons identified one year were known to be present or absent the following year, 57% had a different falcon. This turnover rate was 2-3 times higher than that reported elsewhere for large falcons, and may have been related to high nesting densities in the NCA. Turnover at nesting areas was independent of nesting success in the previous year, but was significantly higher for females nesting on large cliffs. Mean distance between natal and breeding locations for 26 falcons banded as nestlings and later...
Categories: Publication; Types: Citation; Tags: Journal of Raptor Research
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We examined the association between the presence of backpack radiotransmitters and Golden Eagle (Aquila chrysaetos) reproduction (percentage of occupied territories producing young, and number of nestlings produced) over three years. The association between radio-tagging and nesting success and the number of nestlings produced varied significantly among years. A negative association with tagging was observed in one of three years, which coincided with low prey (jackrabbit) populations and a cold spring. However, small sample size and breeding by subadults may confound this result.
Categories: Publication; Types: Citation; Tags: Journal of Raptor Research