Now with a rude smash one of them takes my fly and tears downstream with my line arrowing behind. About 80 yards away the steelhead lunges from the river, and I have a freeze-frame picture of a flash of writhing silver that hangs in my mind’s eye. My line is limp. The brute has escaped. But I feel privileged to have observed a fish accomplishing this marvel of endurance, survival, and homing accuracy.
The steelhead is only one of many creatures whose exploits of navigation daunt the mind. For centuries people have marveled that fish, birds, insects, and other animals find their way over incredible distances to preordained destinations.
“What is most peculiar is that each salmon searches the stream to the place where he was born,” wrote Norwegian clergyman Peder Claussøn Friis in 1599. “From a little narrow fjord at Egersund two rivers flow. There is not a bowshot between the river mouths, yet each river has its distinct salmon, so that one can know the salmon on the one river from that of the other.”
Automotive-age scientists studying the little blackpoll warbler’s fall migration from Nova Scotia to South America—in which the bird loses half its weight in the four-day-and-night, 2,400-mile flight—calculate a fuel efficiency equal to 720,000 miles a gallon.
Monarch butterflies stream from winter roosts in fir trees on a volcanic plateau in central Mexico to summer in northern latitudes, copulating and laying their eggs atop milkweeds to foster new generations along the way. With the old monarchs gone and all ties to the ancestral site ostensibly cut, an incredible thing happens—butterflies that have never been to Mexico roost there the next winter.
The fabled albatross can teach even a U. S. Navy navigator a thing or two. In 1957 scientists banded 18 Laysan albatrosses on Midway atoll in the Pacific and put them aboard Navy aircraft bound for Japan, the Philippines, the Mariana, Marshall, and Hawaiian Islands, and the state of Washington.
Released at these locations, 14 birds returned to Midway. The albatross from Whidbey Island, Washington, 3,200 miles distant, averaged 317 straight-line miles a day. The bird from the Philippines made its 4,120-mile return in 32 days—or about 130 miles a day. Even more remarkable, some of the birds would have had to fly circuitous routes to avoid strong head winds, leading researchers to conclude that “existing theories of bird navigation do not fully explain their homing behavior.”