We satellite-tracked Steller's Sea Eagles (Haliaeetus pelagicus), Black-faced Spoonbills (Platalea minor), and White-naped Cranes (Grus vipio) to determine migration routes and stopover tactics of adult and immature birds. During spring migration, there were no significant differences between adult and immature birds in total migration distance and distance between stopover sites, but the migration period and resting period at stopover sites were significantly longer in immature individuals. There are two possible tactics for migrating without expending fat stores: longer rests or shorter migration distances between stopover sites. Our results suggest that immature birds try to increase fat stores by increasing time available for foraging at stopover sites.
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The Auk
Vol. 119 • No. 3
July 2002
Vol. 119 • No. 3
July 2002
