e insect, nothing is so common as to see the
different species of many genera in conjunction as they fly. The swift
is almost continually on the wing; and as it never settles on the ground,
on trees, or roofs, would seldom find opportunity for amorous rites, was
it not enabled to indulge them in the air. If any person would watch
these birds of a fine morning in May, as they are sailing round at a
great height from the ground, he would see every now and then, one drop
on the back of another, and both of them sink down together for many
fathoms with a loud piercing shriek. This I take to be the juncture when
the business of generation is carrying on.

As the swift eats, drinks, collects materials for its nest, and, as it
seems, propagates on the wing, it appears to live more in the air than
any other bird, and to perform all functions there save those of sleeping
and incubation.

This hirundo differs widely from its congeners in laying invariably but
two eggs at a time, which are milk-white, long, and peaked at the small
end; whereas the other species lay at each brood from four to six. It is
a most alert bird, rising very early, and retiring to roost very late;
and is on the wing in the height of summer at least sixteen hours. In
the longest days it does not withdraw to rest till a quarter before nine
in the evening, being the latest of all day-birds. Just before they
retire whole groups of them assemble high in the air, and squeak, and
shoot about with wonderful rapidity. But this bird is never so much
alive as in sultry thundery weather, when it expresses great alacrity,
and calls forth all its powers. In hot mornings several, getting
together in little parties, dash round the steeples and churches,
squeaking as they go in a very clamorous manner; these, by nice
observers, are supposed to be males serenading their sitting hens; and
not without reason, since they seldom squeak till they come close to the
walls or eaves, and since those within utter at the same time a little
inward note of complacency.

When the hen has sat hard all day, she rushes forth just as it is almost
dark, and stretches and relieves her weary limbs, and snatches a scanty
meal for a few minutes, and then returns to her duty of incubation.
Swifts, when wantonly and cruelly shot while they have young, discover a
little lump of insects in their mouths, which they pouch and hold under
their tongue. In general they feed in a much higher dis