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Grand Teton National Park Report

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A significant population of nesting Bald Eagles (Haliaeetus leucocphalus) occurs in and adjacent to Yellowstone National Park (YNP) and Grand Teton National Park (GTNP). Alt (1980) and Swenson (1975) located 30 Bald Eagle territories within an approximate 15,000 km area encompassing both parks and the surrounding area of southwestern Montana and northwestern Wyoming, designated here as the Yellowstone-Teton area of Influence (YTAI). Although this population is probably essential in producing recruits for the remaining depressed western populations, little is known of the movements and dynamics of this population outside of the breeding season. As a result, a nestling banding project was initiated in the summer of 1979, and expanded to include colormarking in 1980, to determine post fledging movements and population dynamics of Bald Eagles produced in the YTAI. Through band recoveries and returns and resightings of colormarked eagles, attempts will be made to determine: 1) juvenile dispersal patterns 2) immature survival rates 3) longevity 4) wintering areas of YTAI Bald Eagles 5) mortality factors 6) migration routes 7) fidelity to the natal area in successive years 8) importance of the YTAI population in relation to producing recruits for other populations 9) assessment of banding activities on subsequent productivity. With adequate funding, the banding study should continue for at least 3 more years.