Kestrels sometimes build in trees and sometimes in towers and old buildings. But very often they make use of the deserted nest of a magpie or a crow. From four to six eggs are laid, which are blotched with reddish brown on a bluish-white ground.
Two near relatives, inhabiting both the old and the new worlds, are the pigeon-hawk and sparrow-hawk. They are much alike, and their plumage is more varied in color and pattern than that of other falcons. Both are rather shy, and not often seen in the open; but are so courageous that they will sometimes attack large birds, like ducks or grouse. The handsome sparrow-hawk is best known. It will often dash into a flock of sparrows and carry one of them off in its talons. It will sometimes swoop down into a farmyard, too, and snatch up a chicken or a duckling, while numbers of young pheasants and partridges fall victims to its ravages. In days of old it was sometimes captured and trained for hawking, like the merlin and the falcon, and it is said that a single tame sparrow-hawk would sometimes kill as many as seventy or eighty quail in a single day.
In Europe sparrow-hawks seldom take the trouble to build a nest of their own, but nearly always make use of the deserted abode of a crow or magpie, in which they lay three or four grayish-white eggs marked with a number of dark-brown spots and blotches; but the American hawks of this group make their homes in crannies in hollow trees, stuffing the hole with a warm bed of grass and feathers.
Owls, the Terror of the Night
Next in order come those very singular birds which we call owls, and which are really hawks that fly by night.
The eyes of these birds are very much like those of cats, being formed in such a way as to take in even the faintest rays of light. Owing to this fact owls can see on very dark nights, and can fly with as much certainty and catch their prey with as much ease as other birds can in the daylight. Moreover the prominence of their eyes, in the middle of the great feathery disks, enables them to see in almost every direction without turning the head.
This is very important, for wild animals are always alarmed by motion, while they hardly ever notice creatures which keep perfectly still. If you sit or stand for a while without moving even a finger, rabbits and squirrels will often come quite close to you, and never seem to see you at all. But at your very first movement they will take fright and scamper away. So if an owl had to be constantly turning its head from side to side in order to look for prey, its victims would certainly see it, and would make good their escape. But as its eyes are set in the middle of those great feathery circles, and turn easily in their sockets, there is no need for it to do so, for it can look out in almost every direction without moving its head in the least.
There are a good many different kinds of owls, several of which are found in both continents. There is the long-eared owl, for instance, which has two rather long feathery tufts upon its head; and there is the short-eared owl, which has short ones. As a rule, these tufts lie flat upon the head. But when the bird is excited they stand upright, and give it a very odd appearance. Then there is the brown owl, which utters that mournful hooting sound which one so often hears by night in wooded districts.
Very often as one is walking along a country lane in the evening one of these birds sweeps suddenly by and disappears into the darkness. It is busy searching for mice, and the number which it catches must be very great. For it has been found that when a pair of these birds have little ones, they bring a mouse to them about once in every quarter of an hour all through the night! And, besides that, their own appetites have to be satisfied; and owls seem always to be hungry.
One day the late Lord Lilford, one of the foremost British ornithologists of his time, tried to see how many mice a barn-owl really could swallow. So he caught one of these birds and put it in a cage, and gave it seven mice one after the other. Six of these it gulped down without any hesitation; but though it tried hard to swallow the seventh it could not quite manage to do so, and for about twenty minutes the tail of the mouse was dangling from a corner of its beak. At last, however, the tail disappeared; and three hours later the owl was actually hungry again, and ate four more mice!