Other birds than the passing migrants, however, sometimes come within range of my look-out. The year around there are English sparrows and pigeons; and all through the summer scarcely an evening passes when a few chimney-swallows are not in sight. With the infinite number and variety of chimneys hedging me in, I naturally expected to find the sky alive with swallows. Indeed, I thought that some of the twenty-six pots at the corners of my roof would be inhabited by the birds. Not so. While I can nearly always find a pair of swallows in the air, they are surprisingly scarce, and, so far as I know, they rarely build in the heart of the city. There are more canaries in my block than chimney-swallows in all my sky. The swallows are not urban birds. The gas, the smoke, the shrieking ventilators, and the ceaseless sullen roar of the city are hardly to their liking. Perhaps the flies and gnats which they feed upon cannot live in the air above the roofs. The swallows want a sleepy old town with big thunderful chimneys, where there are wide fields and a patch of quiet water. Much more numerous than the swallows are the night-hawks. My roof, in fact, is the best place I have ever found to study their feeding habits. These that flit through my smoky dusk may not make city nests, though the finding of such nests would not surprise me. Of course a night-hawk's _nest_, here or anywhere else, would surprise me; for like her cousin, the whippoorwill, she never builds a nest, but stops in the grass, the gravel, the leaves, or on a bare rock, deposits her eggs without even scratching aside the sticks and stones that may share the bed, and in three days is brooding them--brooding the stones too. It is likely that some of my hawks nest on the buildings in the neighborhood. Night-hawks' eggs have occasionally been found among the pebbles of city roofs. The high, flat house-tops are so quiet and remote, so far away from the noisy life in the narrow streets below, that the birds make their nests here as if in a world apart. The twelve-and fifteen-story buildings are as so many deserted mountain heads to them. None of the birds build on my roof, however. But from early spring they haunt the region so constantly that their families, if they have families at all, must be somewhere in the vicinity. Should I see them like this about a field or thicket in the country it would certainly mean a nest. The sparrows themselves do not seem more at home here than do these night-hawks. One evening, after a sultry July day, a wild wind-storm burst over the city. The sun was low, glaring through a narrow rift between the hill-crests and the clouds that spread green and heavy across the sky. I could see the lower fringes of the clouds working and writhing in the wind, but not a sound or a breath was in the air about me. Around me over my roof flew the night-hawks. They were crying peevishly and skimming close to the chimneys, not rising, as usual, to any height.