Golden Eagle Aquila chrysaetos

Transcription

1 Golden Eagle Aquila chrysaetos Conservation Status Heritage Agency G Rank: G5 USFWS/NOAA: S Rank: S4B,S3N SOA: Species of Greatest Conservation Need BLM: Sensitive USFS: Class: Aves Order: Accipitriformes AA: IUCN: Least Concern Final Rank Conservation category: VIII. Yellow VIII = low status and either high biological vulnerability or high action need Category Range Status: -0 to 0 - Biological: -50 to 50.4 Action: -40 to 40-6 Higher numerical scores denote greater concern Status - variables measure the trend in a taxon s population status or distribution. Higher status scores denote taxa with known declining trends. Status scores range from -0 (increasing) to 0 (decreasing). Population Trend ( to 0) BBS data demonstrates an insignificant increase of 0. between 980 and 007 (P=0.5, n=6, c=3). BBS data for Continental US and Canada demonstrates a significant increase of 3.3% annually (P=0.00, n=334, c=; Matsuoka and Pardieck 009). Declines documented in western U.S., but not Alaska. Data suggests nesting populations in Alaska are stable (Kochert and Steenhof 00). Distribution Trend ( to 0) Likely has stayed the same (Lewis, ADFG, personal communication). Status Total: Biological Population Size ( to 0),077 in Alaska (Rich et al. 004). Review suggests that upward of 00,000 in western North America historically, with,000 to 0,000 breeding pairs in western Canada; Alaskan populations appear stable (Kochert et al. 00). Range Size ( to 0) Breeding range from north slope south throughout Alaska except rare in Kodiak and southcoastal and southeast Alaska. Wintering range more restricted and includes southwest, southcoastal, and southeast Alaska ~60,000 km calculated in GIS. Population Concentration ( to 0) Mainly solitary, but rarely communally roost in unique situations. Reproductive Potential - variables measure aspects of a taxon s distribution, abundance and life history. Higher biological scores suggest greater vulnerability to extirpation. Biological scores range from -50 (least vulnerable) to 50 (most vulnerable). Age of First Reproduction (-5 to 5) Typically do not breed until 4 years of age. Number of Young (-5 to 5) -8.6

2 -3 eggs, Average produced per year young. Ecological Specialization Dietary (-5 to 5) Small to medium sized mammals, especially hares, rabbits, ground squirrels, prairie dogs, and marmots. In the Arctic, also known to ptarmigan, newborn caribou, calves, waterfowl and foxes (Kochert et al. 00, Cade in Schoen and Senner 00). Snowshoe hare and Willow Ptarmigan main prey during breeding season in Interior Alaska. >90% of variation in productivity due to abundance of these prey items. Golden Eagles typically display great plasticity in their diet; however, lack of alternate prey in the north may limit dietary diversity (McIntyre and Adams 999). Habitat (-5 to 5) General habitat is open and semi-open habitats. Breeding habitat in N. and interior Alaska is rugged, mountainous terrain near or above timberline. Also, breeds along bluffs and cliffs along rivers below treeline and sea cliffs in northwest Alaska. In Denali National Park, breeds in alpine and subalpine habitats. Forages on alpine tundra at edges of subalpine scrub in southwest Alaska and tundra river valleys. During winter, forages at edges of woodland shrub habitat in valley floors, riparian areas, and dwarf shrub habitat in Alaska. Biological Total: Action - variables measure current state of knowledge or extent of conservation efforts directed toward a given taxon. Higher action scores denote greater information needs due of lack of knowledge or conservation action. Action scores range from -40 (lower needs) to 40 (greater needs). Management Needs ( to 0) Protected under the Bald and Golden Eagle Protection Act (Bald Eagle Protection Act 940) and the Migratory Bird Treaty Act (MBTA 98). May be taken for falconry with limits (ADFG 004). Monitoring Needs ( to 0) Lack of knowledge about population size and trend; Migration corridors may not be well defined; patterns possibly too diffuse; difficulty of finding, and accessing, suitable migration corridors; finding sufficient, qualified personnel to operate sites; migration count data in Alaska is not reliable to monitor population trends. Golden Eagle observations included in other raptor surveys (i.e. Peregrine Falcon surveys) and monitoring of nesting population in Denali occurs. According to BPIF, need arctic survey, migration monitoring, and improvement of CBC. Research Needs ( to 0) Leading cause of death range wide human induced. Habitat threatened by gas and oil development and riparian substrate removal in the arctic. Very susceptible to nest site disturbance (Snow 973, Schoen and Schenner 00). Annual occupancy of nest sites did not fluctuate with annual changes in prey abundance and weather in interior Alaska, but laying rates, mean brood size, and overall productivity were correlated with abundance of cyclic snowshoe hare and Willow Ptarmigan (McIntyre and Adams 999). Low first year survival due to starvation, electrocution, and poaching may limit recruitment in Interior Alaska. Juveniles in migratory populations of Golden Eagles have lower survival than their non-migratory counterparts. Exposure to Pb may affect Golden Eagles migrating through Canada in the autumn from Alaska (McIntyre et al. 006). Survey Needs ( to 0) Golden eagles well studied by Carol McIntyre in Denali National Park (McIntyre and Adams 999, McIntyre et al. 006). Winter and summer movements of juvenile Golden Eagles was determined by satellite transmitters starting in 007 (McIntyre et al. 008). Research conducted in other areas of Alaska, such as Porcupine River and North Slope (Ritchie and Curatolo 98, Young et al. 995). Distribution also captured by BBS (USGS 006) and ALMS (USGS 008a). Action Total: -6 Supplemental Information - variables do not receive numerical scores. Instead, they that are used to sort taxa to answer specific biological or managerial questions.

3 Harvest: Not substantial Seasonal Occurrence: Year-round Taxonomic Significance: Monotypic species % Global Range in Alaska: >0% % Global Population in Alaska: <5% Peripheral: No Range Map References Alaska Department of Fish and Game (ADFG) Alaska Falconry Manual No. 7. Alaska Board of Game, Alaska Department of Fish and Game. 30 pp. Alaska Department of Fish and Game (ADFG). 005a. Our wealth maintained: a strategy for conserving Alaska s diverse wildlife and fish resources, a Comprehensive Wildlife Conservation Strategy emphasizing Alaska s nongame species. Submitted to the U.S. Fis American Ornithologists' Union (AOU) Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. 89 pp. Armstrong, R. H Guide to the birds of Alaska, 4th ed. Alaska Northwest Books, Anchorage, AK. 3 pp. Bald Eagle Protection Act of 940 (6 U.S.C d, 54 Stat. 50) as amended -- Approved June 8, 940, and amended by P.L (73 Stat. 43) June 5, 959; P.L (76 Stat. 346) October 4, 96; P.L (86 Stat. 064) October 3, 97; an Craig, P. C Fish use of coastal waters of the Alaskan Beaufort Sea: a review. Transactions of the American Fisheries Society 3:65-8. Craig, E. H. and T. H. Craig Results of a helicopter survey of cliff nesting raptors in a deep canyon in southern Idaho. Raptor Research 8:0-5. Dunn, E. H., B. L. Altman, J. Bart, C. J. Beardsmore, H. Berlanga, P. J. Blancher, G. S. Butcher, D. W. Demarest, R. Dettmers, W. C. Hunter, E. E. Inigo-Elias, A. O. Panjabi. D. N. Pashely, C.J. Ralph, T. D. Rich, K. V. Rosenberg, C. M. Rustay, J. M. Rut Gordon, S The Golden Eagle; king of birds. st Am. Ed. Citadel Press, New York. 3

4 Kochert, M. N. and K. Steenhof. 00. Golden Eagles in the U. S. and Canada; status, trends conservation challenges. Journal of Raptor Research 36:33-4. Kochert, M. N., K. Steenhof, C. L. McIntyre, and E. H. Craig. 00. Golden Eagle (Aquila chrysaetos) in A. Poole, P. Stettenheim, and F. Gill, eds. The Birds of North America, No Acad. Nat. Sci., Philadelphia, PA. and Am. Ornithol. Union, Washington Lewis, ADF&G, personal communication Matsuoka, S. and K. Paredieck update on the North American Breeding Bird Survey, Alaska. USGS Patuxent Wildlife Research Center, Laurel, MD. Migratory Bird Treaty Act (MBTA) of July 3, 98, Ch. 8, 40 Stat. 755 (98) (current version at 6 U.S.C ). McIntyre, C. L. and L. G. Adams Reproductive characteristics of migratory Golden Eagles in Denali National Park, Alaska. Condor 0: 5-3. McIntyre, C. L., M. W. Collopy, and M. S. Lindberg Survival probability and mortality of migratory juvenile Golden Eagles from Interior Alaska. Journal of Wildlife Management 70: McIntyre, C. L., D. C. Douglas, and M. W. Collopy Contrasting winter and summer movements of juvenile Golden Eagles. Pp.9 in Alaska Bird Conference March 3-7, 008. Fairbanks, AK. Petersen, M. R., D. N. Weir, and M. H. Dick. 99. Birds of the Kilbuck and Ahklun Mountain Region, Alaska. North American Fauna pp. Rich, T. D., C. J. Beardmore, H. Berlanga, P. J. Blancher, M. S. W. Bradstreet, G. S. Butcher, D. W. Demarest, E. H. Dunn, W. C. Hunter, E. E. Inigo-Elias, J. A. Kennedy, A. M. Martell, A. O. Panjabi, D. N. Pashley, K. V. Rosenberg, C. M. Rustay, J. S. We Ritchie, R. J. and J. A. Curatolo. 98. Notes on Golden Eagle productivity and nest site characteristics, Porcupine River, Alaska, Raptor Research 6:3-7. Sage, B. L Ecological distribution of birds in the Atigun and Sagavanirktok River Valleys, arctic Alaska. Canadian Field-Naturalist 88:8-9. Schoen, J. W. and S. E. Senner (eds.). 00. Alaska's Western Arctic, a summary and synthesis of resources. Draft. December 00. Audubon Alaska. Anchorage, Alaska. Snow, C Golden Eagle (Aquila chrysaetos). U. S. Department of Interior, Bureau of Land Management, Denver, CO, Serv.: Habitat Management Services Unique or Endangered Species; no. 7 (Tech. Note T-N-7). U.S. Geological Survey (USGS) North American Breeding Bird Survey Internet data set. Patuxent Wildlife Research Center. 8 December 006 ( U.S. Geological Survey (USGS). 008a. Alaska Off-road Breeding Bird Survey: Database of Bird Distribution (ALMS). Available online at (Accessed 5/5/008). Watson, J The Golden Eagle. st ed. T. and A. D. Poyser, London, U. K. Young, D. D., Jr., C. L. McIntyre, P. J. Bente, T. R. McCabe, and R. E. Ambrose Nesting by Golden Eagles on the north slope of the Brooks Range in northeastern Alaska. Journal of Field Ornithology 66: Version date: //0 Report authors: K. Walton, T. Gotthardt, and T. Fields Alaska Natural Heritage Program University of Alaska Anchorage Anchorage, AK

5 For details on the development of the ASRS and criteria, please see: Gotthardt, T. A., K. M. Walton, and T. L. Fields. 0. Setting Conservation Priorities for Alaska's Wildlife Action Plan. Alaska Natural Heritage Program, University of Alaska Anchorage, AK. 5