ROM all the lonely salt-flats and tide-washed, reedy shores of the wide estuary, the flocks of the sea-ducks had flown south. After feeding for days together amicably, golden-eyed and red-head, broad-bill and dipper, all hobnobbing and bobbing and guttering in company, without regard to difference of kin, they had at last assorted themselves into flocks of the like species and wing power, and gone off in strong-flying wedges to seek milder tides and softer skies.

Nevertheless, though the marshy levels were now stiffened with frost, and ice fringes lingered thin and brittle behind each retreating tide, and white flurries of snow went drifting over the vast, windy spaces of wave and plain, some bold, persistent waifs of life clung to these bleak solitudes. Here and there a straggler from the flocks, or a belated arrival from farther north, fed solitary and seemed sufficient to himself; while here and there a few hardy coots, revelling in the loneliness and in the forbidding harshness of the season, swam and dived among the low, leaden-coloured waves.

Across ten level miles of naked marsh-land another estuary made in from the sea. On the shore of this estuary, so shallow that for leagues along its edge it was impossible to distinguish, at high tide, just where the water ended and the solid land began, a solitary surf-duck dabbled among the gray, half-frozen grasses. Of a dull black all over, save for a patch of clear white on his head and another on the back of his neck, he made a sharp, conspicuous spot against the pallid colouring of the marshes. For all his loneliness, he seemed to be enjoying himself very well, active and engrossed, and to all appearances forgetful of the departed flocks.

Suddenly, however, he stopped feeding, and sat with head erect and watchful eyes, rising and falling gently with the pulse of the sedge-choked flood. Either some unusual sight or sound had disturbed him, or some drift of memory had stirred his restlessness. For several minutes he floated, forgetful of the savoury shelled and squirming creatures which his discriminating bill had been gathering from among the oozy sedge-roots. Then with an abrupt squawk, he flapped noisily along the surface of the water, rose into the air, and flew straight inland, mounting as he went to a height far above gunshot.

The flight of the lonely drake was toward the shores of the other estuary, ten miles southward, where in all likelihood he had some hope of finding the companionship of his kin, if not a better feeding-ground. Though his body was very heavy and massive and his wings ridiculously short for the bulk they had to sustain, he flew with tremendous speed and as straight as a bullet from a rifle. His wings, however small, were mightily muscled and as tough as steel springs, and they beat the air with such lightning strokes that the sturdy body, head and neck and legs and feet outstretched in a rigid line, was hurled through the air at a speed of something like a hundred miles an hour. As he flew, the flurries of snow gathered into a squall of whirling flakes, almost obscuring the waste of marsh-land that rushed past beneath his flight, and shutting him off alone in the upper heights of sky.

Alone indeed he imagined himself, while the cold air and the streaming snowflakes whistled past his flight. But keen as were his eyes, other eyes keener than his had marked him from a loftier height, where the air was clear above the storm strata. A great Arctic goshawk, driven by some unknown whim to follow the edge of winter southward, was sailing on wide wings through the high, familiar cold. When he saw the black drake far below him, shooting through the snowflakes like a missile, his fierce eyes flamed and narrowed, his wings gave one mighty beat and then half-closed, and he dropped into the cloudy murk of the storm belt.

The drake was now about a hundred yards ahead of the great hawk, and flying at perhaps ninety miles an hour under the mere impulse of his desire to reach the other estuary. When he caught sight of the white terror pursuing him, his sturdy little wings doubled the rapidity of their stroke, till he shot forward at a rate of, perhaps, two miles a minute, his wedge-shaped body and hard, oiled plumage offering small resistance to the air even at that enormous speed. His only chance of escape, as he well knew, was to reach the water and plunge beneath it. But he could not turn back, for the terror was behind him. Straight ahead lay his only hope. There, not more than two or three minutes distant, lay his secure refuge. He could see the leaden gray expanse, touched by a gleam of cold and lonely sunlight which had pierced the obscurity of the squall. Could he reach it? If he could, he would drop into the slow wave, dive to the bottom, and hold to the roots of the swaying weeds till the terror had gone by.

A hundred yards behind came the hawk, moving like a dreadful ghost through the swirl and glimmer of the snow. His plumage was white, but pencilled with shadowy markings of pale brown. His narrowed eyes, fixed upon the fugitive, were fiercely bright and hard like glass. His hooked beak, his flat head, his strong, thick, smoothly modelled neck, were outstretched in a rigid line like those of the drake.

The long, spectral wings of the great hawk beat the air, but not with haste and violence like those of the fleeing quarry. Swift as his wingbeats were, there was a surging movement about them, an irresistible thrust, which made them seem slow and gave their working an air of absolute ease. For all this ease, however, he was flying faster than the fugitive. Slowly, yard by yard, he crept up, the distance from his victim grew narrower. The drake's wings whistled upon the wind, a strange shrill note, as of terror and despair. But the wings of the pursuing destroyer were as noiseless as sleep. He seemed less a bird than a spirit of doom, the embodiment of the implacable Arctic cold.

The astounding speed at which the two were rushing through the sky on this race of life and death brought the gleam of the estuary water hurrying up from the horizon to meet them. The terrible seconds passed. The water was not half a mile ahead. The line of the drake's flight began to slope toward earth. A few moments more, and a sudden splash in the tide would proclaim that the fugitive was safe in a refuge where the destroyer could not follow. But the noiseless wings were now just behind him, just behind and above.

At this moment the fugitive opened his beak for one despairing squawk, his acknowledgment that the game of life was lost. The next instant the hawk's white body seemed to leap forward even out of the marvellous velocity with which it was already travelling. It leaped forward, and changed shape, spreading, and hanging imminent for the least fraction of a second. The head, with slightly open beak, reached down. A pair of great black talons, edged like knives, open and clutching, reached down and forward.

The movement did not seem swift, yet it easily caught the drake in the midst of his flight. For an instant there was a slight confusion of winnowing and flapping wings, a dizzy dropping through the sky. Then the great hawk recovered his balance, steadied himself, turned, and went winging steadily inland toward a crag which he had noted, where he might devour his prey at ease. In his claws was gripped the body of the black drake, its throat torn across, its long neck and webbed feet trailing limply in the air.