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Saint Paul, MN, United States

Mandernack B.A.,Eagle Valley Nature Preserve | Solensky M.,University of Minnesota | Solensky M.,Jamestown | Martell M.,Audubon Minnesota | Schmitz R.T.,Eagle Valley Nature Preserve
Journal of Raptor Research | Year: 2012

We investigated the movement ecology of Bald Eagles (Haliaeetus leucocephalus) that winter along the Upper Mississippi River Valley. During late autumn and winter from March 1999 through February 2006, we outfitted with satellite transmitters 14 wild-caught Bald Eagles (12 adults, 2 subadults) on a winter range or migration stopover point in southwestern Wisconsin. These birds wintered as far south as the Mississippi and Illinois rivers, northwest of St. Louis, Missouri. Summer ranges extended out from the Upper Mississippi River Valley migration corridor as far north as Arviat, Nunavut, Canada, on the western shore of Hudson Bay. Migration route fidelity was apparent, with two notable exceptions. Fidelity to summer and winter ranges also was apparent, but variable. Some eagles remained on a small range the entire season; others traveled extensively, often to the same areas in successive years. Spring migration mean start and end dates for adults were 24 February ± 23 (SD) d and 27 April ± 40 d, respectively. Eagles took from 6151 d to reach their summer ranges (mean: 67 ± 48 d). Mean start and end dates for autumn migration were 21 October ± 28 d and 11 December ± 16 d, respectively; travel duration ranged from 1577 d (mean: 51 ± 20 d). Individual mean straight-line distances between core winter and summer ranges ranged from 6112222 km (mean: 1655 ± 526 km). Our study provided new information on Bald Eagle movement ecology in a vast region where such knowledge was previously lacking. Compared to other tracking studies of Bald Eagles, our study documented greater variation in migration timing and duration, but similar range and route fidelity and distances traveled. © 2012 The Raptor Research Foundation, Inc. Source

Martell M.S.,Audubon Minnesota | Bierregaard R.O.,University of North Carolina at Charlotte | Washburn B.E.,National Wildlife Research Center | Elliott J.E.,Environment Canada | And 3 more authors.
Journal of Raptor Research | Year: 2014

Most North American Ospreys (Pandion haliaetus) are migratory, breeding in northern latitudes and migrating long distances to and from their wintering grounds in the tropics. Although fall migration patterns of North American Ospreys have been described and studied, very little has been published about the spring migration of these birds. We used satellite telemetry to: (1) determine the characteristics (timing, duration, migratory routes) of spring migrations of Ospreys; (2) determine if differences in spring migration patterns existed between sexes and among three breeding populations (east coast, midwestern, and western); and (3) compare consecutive fall and spring migrations of individual Ospreys. The median dates for departure from the wintering grounds and arrival on the breeding grounds did not differ significantly between adult male and female Ospreys. Compared to their fall migrations, all male and all east coast Ospreys spent fewer days on migration, fewer days in stopover periods along the migration route, traveled shorter distances overall, and traveled farther (on average) each day during spring. In contrast, fall and spring migration characteristics of all female and western Ospreys were similar. Our findings suggest that, although sex and breeding location might influence the spring migration strategy used by individual Ospreys, both males and females minimize the time spent on migration to ensure a timely arrival on the breeding grounds to establish or defend a nesting territory. © 2014 The Raptor Research Foundation, Inc. Source

Washburn B.E.,National Wildlife Research Center | Martell M.S.,Audubon Minnesota | Bierregaard R.O.,University of North Carolina at Charlotte | Henny C.J.,U.S. Geological Survey | And 2 more authors.
Journal of Raptor Research | Year: 2014

North American Ospreys (Pandion haliaetus) typically migrate long distances to their wintering grounds in the tropics. Beyond the general distribution of their wintering range (i.e., the Caribbean, South America, and Central America), very little is known about the wintering ecology of these birds. We used satellite telemetry to determine the duration of wintering period, to examine the characteristics of wintering areas used by Ospreys, and to quantify space use and activity patterns of wintering Ospreys. Adult Ospreys migrated to wintering sites and exhibited high wintering site fidelity among years. Overall, Ospreys wintered on river systems (50.6%) more than on lakes (19.0%), and use of coastal areas was (30.4%) intermediate. Ospreys remained on their wintering grounds for an average of 154 d for males and 167 d for females. Locations of wintering Ospreys obtained via GPS-capable satellite telemetry suggest these birds move infrequently and their movements are very localized (i.e., <5 km from selected roosting areas). Sizes of home ranges and core-use areas for wintering Ospreys averaged 12.7 km2 and 1.4 km2, respectively. Overall, our findings suggest wintering adult North American Ospreys are very sedentary, demonstrating a pattern of limited daily movements and high fidelity to a few select locations (presumably roosts). We suggest this wintering strategy might be effective for reducing the risk of mortality and maximizing energy conservation. © 2014 The Raptor Research Foundation, Inc. Source

Kochert M.N.,U.S. Geological Survey | Fuller M.R.,U.S. Geological Survey | Schueck L.S.,U.S. Geological Survey | Bond L.,Boise State University | And 6 more authors.
Condor | Year: 2011

From 1995 to 1998, we tracked movements of adult Swainson's Hawks (Buteo swainsoni), using satellite telemetry to characterize migration, important stopover areas, and movements in the austral summer. We tagged 46 hawks from July to September on their nesting grounds in seven U.S. states and two Canadian provinces. Swainson's Hawks followed three basic routes south on a broad front, converged along the east coast of central Mexico, and followed a concentrated corridor to a communal area in central Argentina for the austral summer. North of 20° N, southward and northward tracks differed little for individuals from east of the continental divide but differed greatly (up to 1700 km) for individuals from west of the continental divide. Hawks left the breeding grounds mid-August to mid-October; departure dates did not differ by location, year, or sex. Southbound migration lasted 42 to 98 days, northbound migration 51 to 82 days. Southbound, 36% of the Swainson's Hawks departed the nesting grounds nearly 3 weeks earlier than the other radio-marked hawks and made stopovers 9.0-26.0 days long in seven separate areas, mainly in the southern Great Plains, southern Arizona and New Mexico, and northcentral Mexico. The birds stayed in their nonbreeding range for 76 to 128 days. All used a core area in central Argentina within 23% of the 738 800-km2 austral summer range, where they frequently moved long distances (up to 1600 km). Conservation of Swainson's Hawks must be an international effort that considers habitats used during nesting and non-nesting seasons, including migration stopovers. Copyright © The Cooper Ornithological Society 2011. Source

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