For a long period associated with the herons and storks, to which they present a marked outward similarity, the cranes differ widely from those birds in the structure of the palate, and the condition of their new-born young, as well as in many features of the anatomy of their skeleton and soft parts. Cranes are now represented by about sixteen species, of which the greater number are confined to Europe, while there are none in South America. Geologically, they are a somewhat ancient group, as remains referred to the existing genus have been obtained from strata of Upper Eocene age.
Although members of the family have been arranged under several genera, it seems on the whole preferable to include all but the crowned cranes in the typical genus. Terrestrial in their habits,- it is said never perching on trees,- all the cranes build on the ground; their huge nests being placed in swamps, and the two or occasionallyy three eggs having a greenish ground more or less spotted with reddish.
The common crane which some centuries ago nested in the British islands, where it is now but a rare visitor, is the typical representative of the genus, and is characterized by the moderate length of its beak. cranes usually reach their breeding grounds in central Europe from the south at the end of March or April, while a month later they arrive in the Arctic regions. At all times gregarious, they migrate in vast flocks, which fly during the day at a great height in the air in a V- or W- shaped formation, each bird having its long legs stretched out behind. Each bird keeps his place in the ranks; the advancing column now rides higher over some suspected spot, now falls along an open sandy reach, swaying meanwhile to the right or left. As it passes on, the individual birds are blended in the hazy distance, till, just before lost to view, the line becomes like an immense serpent gliding mysteriously though the air. When about to alight, fearful lest the shadows of the woods harbor unseen dangers, the cranes pass by the leafy intricacies where the ibises and other less suspicious birds feed, and choose a spot for the advantages it may offer of uninterrupted vision. By nature one of the most wary and discreet of birds, his experience has taught the crane to value this gift and put it to the best use. His vigilance is rarely relaxed, even when he is feeding, where less thoughtful birds would feel perfectly secure. This wariness renders the crane an exceedingly difficult bird to shoot; although the flocks frequenting the sandbanks of the Indian rivers may be readily approached in a boat, to the passing of which they are indifferent. Cranes feed regularly in the early morning, and also at other times in the day, and at night; while the vast quantity of grain a flock will consume, renders their visits by no means welcome to the cultivator. In sleeping, they invariably stand upon one leg, with the head and neck thrust in among the plumage of the back. In the bogs of Lapland the crane breeds in vast numbers; the nest being made of small twigs intertwined with long, sedgy grass, its diameter being about 2 feet, and its depth several inches.
The sarus crane of India, which attains a length of 52 inches, together with the nearly allied Australian crane represent a second group of the genus, characterized by the longer beak, and by the head and neck being bare and covered for 3 or 4 inches with numerous crimson warts, from which grow scanty black hairs, mostdeveloped down the nape. The sarus is always found in the neighborhood of water, and is less gregarious than the common species, being generally seen in pairs. It is also far less of a grain-eating bird; while, except when driven by drought, it does not migrate. It is likewise tame and confiding, and so attached are the members of a pair that on occasions the survivor will pine away and die on the death of its mate .
Far more beautiful than either of the foregoing is the lovely white crane, inhabiting a vast area in Central and Northern Asia, and migrating in winter to India, and probably other Asian countries. This Asiatic species has been called the lily of birds. This crane is found only where there are large sheets of shallow water, in which grow an abundance of the rushes and other aquatic plants forming it chief nutriment. To show how deceptive is the appearance of cranes when seen from a distance, they have been mistaken for antelope.
Among the numerous other members of the genus, space permits of reference to only a few. Of these the great wattled crane of South Africa, takes its name from the presence of two feathered flaps of skin depending from the chin. This crane goes about in pairs, which haunt locality for years. The pretty demoiselle crane, which breeds in north Africa , Spain, Southern Russia , and a large area of Central and Eastern Asia, while in winter it visits Central Africa and India. In India, where it arrives late in October, this crane associates in flocks comprising from fifty to one hundred individuals, and frequents rivers rather than marshes. Being mainly a vegetable-feeder, it is very destructive to grain. The eggs are olive green speckled with rufous; and, while the female is sitting, the male keeps constant guard. Allied to this species is the much larger Stanley crane, often referred to the distinct genus Tertrateryx of South Africa, in which the whole plumage is leaden-blue, with the exception of the white crown of the head and the black extremities of the drooping secondaries. This species, although widely distributed, is nowhere abundant, and is always found in pairs. It inhabits areas a great distance from water and is mainly carnivorous. In confinement it becomes extremely tame, although in the wild state it is very shy. The two species of African crowned cranes take their name from the narrow fan-shaped crest of twisted bristle-like feathers radiating from an elongated center on the top of the head, by which they can be immediately recognized.
