de.

Water birds find the best sleeping-places on the water, where they float
all night like tiny boats. Some of them leave one foot hanging down and
paddling a little, while they sleep, to keep from being washed to the
shore.

Bob-white and his family sleep in a close circle on the ground, all with
their heads turned outward, so that they can see or hear an enemy,
whichever way he comes.

Hawks and eagles are said to sleep standing, never sitting on the feet
like a canary. Some ducks and geese do even more: they sleep standing on
one foot. Woodpeckers and chimney swifts hang themselves up by their
claws, using their stiff tail for a brace, as if it were a third leg.

Some birds, like the crows, sleep in great flocks. They agree upon a
piece of woods, and all the crows for miles around come there every
night. Sometimes thousands of them sleep in this one bedroom, called a
crow roost. Robins do the same, after the young are big enough to fly so
far.

Audubon, who has told us so much about birds, once found a hollow tree
which was the sleeping-room of chimney swifts. The noise they made going
out in the morning was like the roar of a great mill-wheel.

He wanted to see the birds asleep. So in the daytime, when they were
away, he had a piece cut out at the foot of the tree, big enough to let
him in, and then put back, so the birds would not notice anything
unusual.

At night, after the swifts were abed, he took a dark lantern and went
in. He turned the light upon them little by little, so as not to startle
them. Then he saw the whole inside of the tree full of birds. They were
hanging by their claws, side by side, as thick as they could hang. He
thought there were as many as twelve thousand in that one bedroom.

II. HIS TRAVELS

Most of our birds take two long journeys every year, one in the fall to
the south, and the other in the spring back to the north. These journeys
are called "migrations."

The birds do not go all at once, but in many cases those of a kind who
live near each other collect in a flock and travel together. Each
species or kind has its own time to go.

It might be thought that it is because of the cold that so many birds
move to a warmer climate. But it is not so; they are very well dressed
to endure cold. Their feather suits are so warm that some of our
smallest and weakest birds are able to stay with us, like the chickadee
and the golden-crowned kinglet. It is simply because they cannot