Northern Africa presents us with a beautiful White Heron, about the size of a Pigeon, the functions of which are extremely interesting; it is called the Ox-keeper. In Morocco this bird is very common. It is in the habit of accompanying the oxen into the fields, and takes the task of relieving the latter from the numerous flies and insects with which they are annoyed. In France it is met with only at the mouth of the Rhône.
The Bittern (Botaurus) has both the neck and legs shorter than those of the Grey Heron; its plumage is of a rich reddish yellow, boldly variegated with dark markings. Districts intersected by marshes are the chief places of its resort; in these it keeps itself hidden all day long among the reeds, motionless and silent. Here, too, it makes its nest, almost on the ground, and close to the water. It does not leave its hiding-place until the evening, and then will fly up to so great a height as to be lost to view. Its call to its mate is peculiar; it resembles the bellowing of a bull, and can be heard more than half a league away. For this reason the ancients called it Bos taurus—whence, by corruption, comes the French Butor.
The Bittern is a very courageous bird; it will defend itself energetically against any bird of prey, against dogs, and even man. It is found all over Europe. Four British species are described—B. stellaris, B. lentiginosus, B. minutus, and B. comatus.
The Crane (Grus), which forms a genus among the Cultrirostres, is characterised by a bill much longer than the head, stout, straight, tapering, compressed, and pointed, but always slightly cleft; feet long; tibia bare for a fourth of its length, covered with hexagonal scales; toes, four; back toe short, which does not reach the ground; wings long and pointed. The Cranes are essentially migratory birds, and possess wonderful requisites; for, in addition to prolonged powers of flight, they enjoy the valuable faculty of being able to endure total abstinence from food for several days—a faculty which, we may remark, is common to most of the Wader tribe, though in a less degree.
There are three species described—the Ash-coloured Crane, the Crested Crane, and the Demoiselle Crane.
The Ash-coloured Crane (Grus cinerea), [Fig. 142], is a fine bird, attaining nearly five feet in height. With the exception of the neck, which is black, all the rest of its body is of a uniform ashy-grey colour. The carriage of the bird is noble and graceful, and the feathers on its rump, which rise up in undulating clusters, add much to its elegance.
Fig. 142.—Ash-coloured Crane (Grus cinerea, Temm.).
These Cranes are periodical visitors to France; they arrive in Europe in the month of April or May, passing the fine weather in more northern countries. Towards the middle of October, on the arrival of the first cold weather, they leave us, in order to winter in Egypt, Abyssinia, or even Southern Asia. They travel in flocks, numbering sometimes as many as three or four hundred birds; generally they arrange themselves in two lines, so as to form an isosceles triangle, or a sort of wedge with the point in front—the most convenient formation for cleaving the air with the least amount of fatigue. From time immemorial people have been fond of saying that these birds intrust the care of their guidance to a chief, who, after having led the way for a certain time, and becoming wearied, surrenders his charge to one of his companions and passes to the rear of the band, where, like a new Cincinnatus, he resumes the position of a simple citizen. The fact is, that the leader of the two files changes perhaps ten times in a minute, and the apex of the angle is occupied in succession by every Crane in the flock within a very short space of time.
Cranes almost always travel at night, and alight down on the ground during daytime to seek their sustenance. Sometimes, however, they do not stop, and continue to push on through space, giving utterance to startling cries, which probably are intended as a rallying summons to those of the band which seem tempted to linger on their journey. When they perceive a bird of prey, or have to contend against a tempest, they abandon their usual formation, and collect in a circular mass, so as better to resist the enemy.