But the other birds are nowhere to be seen. Where are they? It is not easy to find them, for they hide themselves, from fear of the owls, the weasels and the stoats, and they wake and flutter away very soon if you come near them.

The small birds sleep chiefly in the hedges. You will be surprised how difficult it is to see them, even in winter when the leaves are off the trees; for the twigs and branches crossing each other hide them well. No owl or hawk could seize a bird in a hawthorn hedge.

But how do they keep themselves upon the twigs when they are fast asleep? If you or I tried to sleep standing up we should fall. For our muscles would grow slack, our heads would nod, and our knees would give way under us.

It is different with a bird. He sits on a branch, and grasps it with his claws. Then he squats down and bends his legs. As he does this, a muscle round his knee-joints pulls the muscles of his tows quite tight, so that his claws are kept clasped round the branch. He cannot move till he had raised himself up and straightened his legs, and thus set his claws free. So the more soundly he sleeps the tighter he grasps the bough, and the less likely he is to fall.

Birds sleep out of doors both summer and winter, and they have a curious covering to keep them warm. It is made of air. When a bird goes to roost, he tucks his head under the plumage of his shoulder, and puffs out his feathers, so that the air gets in between them, and settles all among the soft down which grows close to his body. This air soon becomes warm, and, as it cannot get out, it prevents the bird's warm body from being chilled by the cold air outside.

Still, in bad weather birds often like to find warm nooks to sleep in. House-sparrows, tits, wrens, and other small birds sometimes make holes in hay-stacks for their beds. The owls keep themselves warm in barns, church towers, and sometimes in holes in the trunks of trees. The blue-tit loves to sleep under a thatched roof, and Wrens often hunt up old nests in winter, and huddle together in them to keep themselves warm.

Swallows and swifts do not want to be kept warm, for they fly south in cold weather. In summer they perch on the rafters in the barns, and if you go into a barn after dark, you may often hear them flitting from one rafter to another if they are disturbed.

Wood-pigeons roost on the fir-trees in the wood, and hawks on the branches of the taller trees. Pheasants, too, roost in the trees of the wood, and it is curious that they always tell you where they go to bed. For they call "crok, crok," as they settle down to sleep.

But partridges sleep on the ground in the fields. They lie in a circle with their heads outwards and their tails together. The father generally sleeps a little way off as a sentinel. Then if a fox, or a weasel, tries to catch them in their sleep, any one that is awake and sees the enemy can give the alarm to the rest.

All these birds sleep inland in the woods and fields. But if you can go to the sea-shore some summer evening and lie on the beach under the high cliffs, you may see other birds coming home to roost. Just as the sun is setting many little birds from the fields perch in the bushes at the top of the rocks. Next come any jackdaws, which happen to live near the sea, cackling and chasing each other over the cliffs. They creep into holes to sleep. Then a few big cormorants sail in from the sea, followed by the gulls, and settle on the ledges half-way down the face of the cliff. Some croaking ravens come flying from the land, and twist and tumble about, before they too sit down for the night. The sand-martins disappear into their holes in the sandstone-rocks, and perhaps a falcon will come circling round in the air and swoop down in some quiet nook.

Then after a time the cackling and the croaking cease and as the moon rises all is quiet. But if you look on the silvery water you will see that many of the gulls are still floating on the waves, and they may remain there all the night.

Watch the birds going to roost at night, and notice their special haunts.