Movements by juvenile and immature Steller's Sea Eagles Haliaeetus pelagicus tracked by satellite
Abstract:Twenty-four juvenile Steller's Sea Eagles Haliaeetus pelagicus were tracked via satellite from natal areas in Magadan, Kabarovsk, Amur, Sakhalin and Kamchatka. Nestling dispersal occurred between 9 September and 6 December (n = 24), mostly 14 September–21 October, and did not differ among regions or years. Most eagles made stopovers of 4–28 days during migration. Migration occurred 9 September–18 January, mostly along previously described routes, taking 4–116 days to complete (n = 18). Eagles averaged 47.8 km/day excluding stopovers; 22.9 km/day including stopovers. The mean degrees of latitude spanned during migration was: Kamchatka, 2.1; Magadan, 11.6; Amur, 7.3; and Sakhalin, 1.1. Eagle winter range sizes varied. Eagles concentrated in 1–3 subareas within overall winter ranges. The mean size of the first wintering subareas was 274 km2, the second 529 km2, and the third 1181 km2. Second wintering areas were south of first wintering areas. Spring migration started between 2 February and 31 March. Two eagles from Magadan were tracked onto summering grounds, well south of their natal areas. Both had early and late summering areas. One bird was followed for 25 months. It initiated its second autumn migration in the first half of October and arrived on its wintering grounds on 26 December. The second autumn migration covered 1839 km (20.9–22.4 km/day). Unlike its first winter when it used two subareas, this bird used only one subarea in 1998–99, but this was located near wintering areas used in 1997–98. It left its wintering ground between 13 April and 13 May, and arrived on its summering grounds between 7 June and 8 July. Unlike most satellite radiotracking studies, data are presented from a relatively large number of birds from across their breeding range, including new information on eagle movements on the wintering grounds and during the second year.
Document Type: Research Article
Affiliations: 1: Forest and Rangeland Ecosystem Science Center, Snake River Field Station, Boise State University-Raptor Research Center, 970 Lusk St., Boise, ID 83706, USA 2: Research Center, Wild Bird Society of Japan, 2-35-2 Minamiadara, Hino, Tokyo, 191-0041 Japan 3: Institute of Biological Problems of the North, Russian Academy of Sciences, Magadan, Russia 4: Magadan State Reserve, Portovaya St., 8, 685000 Magadan, Russia 5: Department of Vertebrate Zoology, Moscow State University, 119899 Moscow, Russia 6: Science Park, Moscow State University, Vorobyovy gory, 119899 Moscow, Russia 7: Center for Conservation Research and Technology, University of Maryland Baltimore County, Room 105, TRC Building, 5200 Westland Boulevard, Baltimore, MD 21227, USA 8: Soldier Biological and Chemical Command, Aberdeen Proving Ground, MD 21019, USA
Publication date: 2003-04-01