lows, with long forked tails; cliff swallows, with cream-white foreheads; bank and rough-winged swallows, with brown backs—the air was full of their whirling, curving flight. With them went their big brothers, the purple martins, and the night hawks, with their white-barred wings, which at times, as they whirled downward, made a hollow twanging noise. With the flock, too, were the swifts, who sleep and nest in chimneys, and whose winter home no man yet has discovered.
As the turquoise of the curved sky deepened into sapphire, a shadowy figure came toward the circling, flashing throng of swifts and swallows. The newcomer's great bare wings seemed made of sections of brown parchment jointed together unlike those of any bird. Nor did any bird ever wear soft brown fur frosted with silver, nor have wide flappy ears and a hobgoblin face. Miles above the ground this earth-born mammal was beating the birds in their own element. None of the swallows showed any alarm as the stranger overtook them, for they recognized him as the hoary bat, the largest of North American bats, who migrates with the swallows and, like them, feeds only on insects.
As the sun sank lower, the great company of the bird-folk swooped down toward the earth, for swallows, swifts, and martins are all day-flyers. Not so with the bat. In the fading light, he flew steadily southward alone—but not for long. Up from earth came again the great gyrfalcon, his fierce hunger unsatisfied with the few mouthfuls torn from the
