Eagle On the Edge - Living in the forbidding terrain of Russia's Far East, Steller's sea eagle may be the most impressive raptor you've never heard of

International Wildlife, Sept-Oct, 2000 by Lucille Craft

From December to March, Ladyguin and his wife watched from their igloo as sea eagles fed at Kuril Lake. The birds roost communally in stands of birch and large rocks near the shore, flying out to the water to dive for fish.

As spawning winds down and fish become scarce, the communal roost serves as a communications center.

"Eagles flapping in a particular direction will soon catch the attention of the birds still in the roost, and the 'word' will spread," Ladyguin says.

In mid-March, Ladyguin followed the migrating eagles to their summer range at the Kronotskiy reserve, a 3,721-square-mile sanctuary that contains the Valley of the Geysers, a popular stop for American cruise ship tourists. There, Ladyguin set up blinds to watch the previously unrecorded nesting behavior of the sea eagles on Kamchatka.

Built in the crowns of trees as high as 70 feet, the nests have a nasty tendency to topple. And the only thing between a fragile egg and gale- force blizzards is its mother, which is probably why female eagles weigh as much as about 7 pounds more than males. Leaving the white or bluish eggs uncovered even briefly during the often frigid 36-day incubation period spells doom for the young. Of the eggs produced each year on Kamchatka only one-third to one-half will survive to fledging, not only because of exposure, but also because of predation by sable and collapsing nests.

Eagles supplement their favorite food, salmon, with edibles that wash onto the beach-sea cucumbers, octopuses and dead fish. By July, after the young have hatched, the salmon schools have moved inland, in such numbers that sometimes Ladyguin can't avoid hitting them with his canoe paddle. The scientist watches as eagles dive into the river, emerging laboriously moments later with silver salmon firmly in their talons. The birds fly to the nearest shallows, pin the fish to the ground and tear off and swallow several large chunks of flesh. Once sated, the eagles take the leftovers to their nests, where their offspring wait impatiently.

This gourmet diet of pure salmon is like a magic growth hormone. Ladyguin found that the downy 5-ounce nestlings multiply in weight 40 times in less than two months. This prepares them for the long flight to Kuril Lake and other points south, when the lakes in northern Kamchatka freeze over and lock up their food supply.

While Ladyguin was sketching in the details of the raptor's life in Kamchatka, other researchers were beginning to trace the route of the bird's travels to and from Russia. For years bird-watchers in Hokkaido, Japan's northernmost island, had witnessed the arrival of Steller's eagles each November. But it wasn't until 1995, when Mutsuyuki Ueta, a researcher with the Wild Bird Society of Japan, and other scientists began attaching small transmitters to chicks at Russian nesting sites around the Sea of Okhotsk, that their migration was fully understood. Ueta and others were surprised to learn that few Kamchatkan eagles end up in Japan. Many of the nearly 2,000 wintering eagles in Hokkaido hailed from the Amur River area, with some traveling from as far north as Magadan, on the Russian mainland. In recent years, Japan has become merely a way station in the fall, as the eagles continue east to the fish-rich southern Kuril Islands off the coast of Hokkaido. But as snow and ice put the Kuril fish out of reach, the eagles fly back to Hokkaido for the remainder of the winter.