stival or
grand celebration; and, as if bent upon a final effort to work off a
part of their superabundant wing-power before settling down for the
night, they circle and circle high above the chimney-top, a great
cloud of them, drifting this way and that, all in high spirits and
chippering as they fly. Their numbers constantly increase as other
members of the clan come dashing in from all points of the compass.
Swifts seem to materialize out of empty air on all sides of the
chippering, whirling ring, as an hour or more this assembling of the
clan and this flight festival go on. The birds must gather in from
whole counties, or from half a State. They have been on the wing all
day, and yet now they seem as tireless as the wind, and as if unable
to curb their powers.

One fall they gathered in this way and took refuge for the night in a
large chimney-stack in a city near me, for more than a month and a
half. Several times I went to town to witness the spectacle, and a
spectacle it was: ten thousand of them, I should think, filling the
air above a whole square like a whirling swarm of huge black bees, but
saluting the ear with a multitudinous chippering, instead of a
humming. People gathered upon the sidewalks to see them. It was a rare
circus performance, free to all. After a great many feints and playful
approaches, the whirling ring of birds would suddenly grow denser
above the chimney; then a stream of them, as if drawn down by some
power of suction, would pour into the opening. For only a few seconds
would this downward rush continue; then, as if the spirit of frolic
had again got the upper hand of them, the ring would rise, and the
chippering and circling go on. In a minute or two the same manoeuvre
would be repeated, the chimney, as it were, taking its swallows at
intervals to prevent choking. It usually took a half-hour or more for
the birds all to disappear down its capacious throat. There was always
an air of timidity and irresolution about their approach to the
chimney, just as there always is about their approach to the dead
tree-top from which they procure their twigs for nest-building. Often
did I see birds hesitate above the opening and then pass on,
apparently as though they had not struck it at just the right angle.
On one occasion a solitary bird was left flying, and it took three or
four trials either to make up its mind or to catch the trick of the
descent. On dark or threatening or stormy days the bird