The wintering of 1989 in the lake Kuril (South Kamchatka) basin sheltered 650— 700 of the white-shouldered eagles, 20—25 golden eagles and 20—25 white-tailed eagles. It was the hugest wintering in the area of the species. The population peak was registered in December—January, and in March the wintering discharged. The eagles prefered after-spawring salmons (90% of their catch). Mass cleptoparasitism was ascertained. The eagles picked up nearly 4% of the total sock-eyed salmon population at the lake spawning grounds, and nearly 0,5% — at the river spawning grounds. During the winter eagles picked up nearly 15 thousand sock-eyed salmons (0,6% of the spawners). The impact of eagles upon the reproductive part of the sock-eyed salmon population was found to be inessential.