



the winter, some of the birds migrate to 

 Japan and Korea, but about 1,000 individ- 

 uals, or one-eighth of the world's popula- 

 tion of Steller's eagles, remain at Kuril 

 Lake to feed on its riches. 



Unlike bald eagles of North America, 

 which have attracted the attention of biol- 

 ogists, conservationists, and ecotourists, 

 Steller's sea eagles are little known and are 

 studied today by only a handful of scien- 

 tists. The haunts of the bird are remote, 

 and this may account for its extreme shy- 

 ness with humans. No roads lead to Kuril 

 Lake, and the nearest village lies some 

 sixty miles away. A scientific station has 



Spawning sockeye salmon, below, choke the feeder streams of 

 Kuril Lake and sustain a wealth of bird life all winter. White- 

 tailed and golden eagles, ducks, swans, ravens, crows, and some 

 small songbirds, as well as Steller's eagles, left, partake of the 

 spoils of salmon eggs and carcasses. 



an outpost on the one river that flows from 

 the lake to the sea. The limited access to 

 the region and the bitter weather make for 

 hard living conditions for scientists in 

 winter. But like other visitors to this area, 

 we enjoy plenty of fresh salmon and 

 caviar. 



Among themselves, Steller's sea eagles 

 are extremely gregarious. Even in the 

 breeding season, when many species of 

 birds forgo flocks for family groups and 

 hunt singly or in pairs, Steller's eagles 

 tend to feed communally. This habit is re- 

 lated to their specialization as fish eaters; 

 fish, their main food year-round, tends to 

 be concentrated in lakes and streams. 

 Most Steller's sea eagles in Kamchatka 

 breed along the more northerly coasts of 

 the peninsula. Beginning in late March, 

 the eagles begin to refiirbish their huge 

 nests, which they use year after year. The 

 usual clutch consists of two eggs, and the 

 parent birds raise the eaglets on chunks of 

 freshly caught fish until the young birds 

 fledge by summer's end. As early as Sep- 



tember, the leaves fall, the icy winds of 

 winter begin, and the eagles' lives change 

 dramatically. The lakes in northern Kam- 

 chatka freeze over, locking up their food 

 supply. Adults, subadults (eagles less than 

 five years old), and the young of the year 

 wander southward and congregate in large 

 groups, becoming even more social than 

 in summer. Of the thousand or so eagles 

 that take up winter residence on Kuril 

 Lake, I have seen more than four hundred 

 gather on one feeder stream choked with 

 salmon. As soon as one eagle finds a car- 

 cass, other eagles quickly gather The evo- 

 lution of this intensely social foraging sys- 

 tem, and the central role it plays in the 

 birds' general ecology, is the focus of 

 much of my winter work. 



I beheve that the size of then- prey ex- 

 plains why feeding Steller's eagles attract 

 one another and, indeed, rarely feed inde- 

 pendently, even when food abounds. It 

 certainly contributes to the varied interac- 

 tions of Steller's and other species of ea- 

 gles. Adult sockeye salmon average about 



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