THE DIVERS (Urinatores).
THE birds belonging to this extensive order are all aquatic, and almost exclusively subsist on fishes, which they capture by diving. In conformity with this mode of life, they all present a general type of structure which is unmistakable. Their bodies are powerfully built, almost cylindrical in shape, and their legs placed far backwards. Their wings are short, feeble, and pointed, but little adapted to flight, and in many cases almost resembling fins, while their dense smooth plumage, which is impenetrable to water, admirably fits them for a residence in that element. Their beak is strong, hard, acutely pointed, and generally compressed at the sides; it is seldom much longer than the head, and its margins are usually sharp and well adapted for cutting. The foot is furnished either with three or four toes, of which the three in front are either strongly-webbed or furnished with lateral expansions of the skin, which render them efficient instruments of propulsion. The tail is often altogether wanting, or if present is always short, rounded, and generally formed of more than twelve feathers. There is much similarity in the coloration of their plumage, in which black and pure white predominate; in some species, however, variety of colour is not wanting. Generally speaking, these birds are all inhabitants of the sea; nevertheless, a few are to be met with only in inland lakes: some species have a very wide range in a great variety of climates; but the majority prefer the polar regions of the world, both north and south, from which, however, some of them migrate at stated intervals. The greater part of their lives is passed upon the surface of the water; indeed, it is only during the breeding season that they come upon dry land. Although many species fly with tolerable facility, in most instances the wings are too feeble to support the weight of their bodies, and are principally used almost like fins, to enable them to progress more rapidly when diving beneath the surface of the water, where they obtain the fishes and small crustaceans that constitute their usual food. A few diving birds build their nests solitarily; but by far the greater number congregate in innumerable hosts, and breed in company with each other upon rocks and islands that rise abruptly from the sea. The eggs are two in number.
The GREBES (Podicipites) are only to be met with in fresh water, and accordingly are classed by some naturalists in the immediate vicinity of the Coots, to which, as far as relates to the structure of their feet, they certainly bear a considerable resemblance. Their true position, however, we consider to be undoubtedly among the Divers. Their body is remarkably broad and squat; their neck long and moderately slender; their head small and elongated; their beak long, conical, and compressed at the sides, with incurved, sharp cutting edges, the lower mandible being slightly overlapped by the upper one. The legs are placed so far backward, that they seem to be attached quite to the posterior extremity of the body, and moreover are of very peculiar conformation. The tarsi are of moderate height, and so much compressed at the sides that the front of the instep presents a sharp smooth edge. The structure of the foot is likewise remarkable; of the three front toes, the exterior is as long or longer than the middle toe, while the inner toe is by far the shortest of the three; the hinder toe, which is slightly elevated, is a mere rudiment. The three front toes are connected by a web as far as the first joint, but beyond this point they are separated, although each is furnished on both sides with a broad fold of skin, which is not scalloped, but smoothly rounded off in front, where it is further strengthened by the broad flattened claws. The wings are small, short, and narrow, the second and[Pg 241] third quills being longer than the rest. The tail is altogether wanting, its place being occupied by a small bunch of fur-like feathers. The general plumage is everywhere very thick, and upon the lower part of the body so smooth and bright as almost to resemble satin, while on the head, neck, and hinder part of the body it has somewhat the appearance of hair. When in their nuptial plumage, the head of the adults is adorned with a remarkable collar or frill, developed from the sides of the face and neck, or provided with bunches of feathers, generally decorated with bright colours. Members of this family are to be found in the temperate zones of both hemispheres, beyond which they do not extend very far either to the north or south. Their usual habitat is on ponds or large sheets of stagnant water, and exceptionally on deep, slow-moving streams; but always where sedges and rushes are abundant. Occasionally, though rarely, they have been seen upon the sea. "Probably there are no birds," says Naumann, "better entitled to the name of water-fowl than the Grebes"—at least we know of no others that do not on some occasions make their appearance on dry land. It is only, however, under the most urgent circumstances—as, for example, when wounded—that these approach the shore, and even then they keep so close to the brink that on the slightest alarm they can at once plunge into their proper element. It would seem that whatever they do must be done in the water; they cannot even rise upon the wing without a preliminary rush over the surface of the lake: from dry land they cannot commence their flight. Their whole life is divided between swimming and diving; and even when other water-birds go on shore to sleep, the Grebes repose floating on their liquid bed. When thus sleeping upon the tranquil water, they float as buoyantly as if they were made of cork, their legs raised to the edges of their wings, and their head comfortably buried among the feathers between their back and shoulder. Should, however, a storm disturb their rest, and the boisterous elements drive them towards the shore, they at once turn round to face the blast, and are generally able, by the active movement of their paddle-like feet, to maintain themselves in the same place.
The conformation of their bodies, their tapering shape, small heads, sharp beak, and the very backward position of their feet, enable them to dive with wonderful facility; in fact, when under water they make their way more swiftly than even when swimming at the top. A man upon the shore would find it very difficult to keep pace with a diving Grebe, as, aided by wings and feet, it shoots onwards with the velocity of a rocket. When flying, their long neck is stretched out straight forwards and their feet backwards, while their small wings, by the rapidity of their movements, carry them very quickly through the air. In the absence of any tail, they steer their course by means of their feet, and are able not only to direct but to change the course of their flight with surprising facility; at the end of their journey they come down obliquely upon the surface of the water, into which they fall with a very audible splash. When alarmed they always instantly dive, and nothing but the utmost extremity of danger will compel them to take wing. The food of these birds consists of small fishes, insects, frogs, and tadpoles, in search of which they dive to the very bottom of the pond, but always bring them to the top before swallowing them. In their manner of breeding, the Grebes are in many respects peculiar. They live together in pairs, the male and the female exhibiting the greatest affection towards each other, keeping each other company even during their migrations, and always returning together to the same pond. When the time arrives, they construct a floating nest, which, instead of being built of dry materials, as in the case of other birds, is merely a mass of wet weeds, in which the eggs are kept not only constantly damp, but absolutely in the water. The weeds used in building the nest are procured by diving, from the bottom of the pond; these are put together in the most slovenly manner, so as to resemble a floating heap of rubbish rather than a nest, and are then fastened to some old upright reeds. The number of the eggs varies from three to six; they are of elongated shape, and at first of a greenish white colour, but they soon become dirty, and are then of a yellowish red or olive-brown tint, sometimes marbled.
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The male and female sit upon the eggs alternately, but the female has the greater share in the business of incubation, the male often swimming around the place apparently for the purpose of keeping her company. Should, however, both be obliged to leave the nest at the same time, they carefully cover the eggs with a mass of half-rotten water-plants, brought up from the bottom for the purpose. In about three weeks the young are hatched, even from eggs which during a great part of the time have been lying in the water. From the first moment they are able to swim, and in the course of a few days to dive; they are, however, constantly accompanied by their parents, who often give them shelter under their wings. Having once quitted the nest, the young ones seldom return to it, a comfortable resting and sleeping place being afforded to them on the backs of their parents.
THE CRESTED GREBE.
The CRESTED GREBE (Podiceps cristatus), the stateliest member of the family, is a bird of considerable size, measuring from twenty-five to twenty-six inches in length, and from thirty-six to thirty-seven in breadth. The length of the wing is seven inches. During the time of its courtship this bird is furnished with a very remarkable head-dress, consisting of a large bunch of long feathers, divided above into two horn-like appendages, and also with a prominent collar or frill of hair-like plumes, on each side of the upper extremity of the neck and sides of the head. The upper parts of its body are of a shining blackish brown, a bright patch on each wing; the region of the cheeks and the throat are white; the collar around the neck rust-red, with a blackish brown margin. The under part of the body is of a glossy satiny white, speckled upon the sides with rusty red and dark grey. The eye is carmine-red, the bridles red, the beak pale red; the outer aspect of the tarsus is dark horn-colour, and the inner side yellowish grey. In its winter garb, the tufts upon the head and the collar are not developed, the brown upon the upper part of the body is mingled with deep grey, and the rust-red of the collar as well as the rust-brown of the sides is duller. The female is distinguishable from the male by her smaller size, but not by any difference in her colour. The young birds are less beautiful than are the adults in their winter dress, and are striped about the head and neck. The nestlings are at first clothed in greyish brown, streaked with black.
The Crested Grebe is to be met with wherever suitable pieces of water exist over all parts of Europe south of 60° north latitude. It is by no means scarce in Germany, and is still more abundant in lakes further to the south. In England it is principally met with in Shropshire and Lincolnshire, and is reckoned as a stationary bird even in Zetland. In the northern countries it makes its appearance early in the spring, generally in April, or shortly after the melting of the snow, and remains until October or November, when it retreats to Southern Europe and Northern Africa. In Greece and Spain it remains all through the winter; indeed, the numbers to be met with in those countries are considerably augmented by arrivals from localities further north. In North-western Africa it likewise makes its appearance at regular intervals, but in Egypt only a few solitary birds are to be met with. In Central and Northern Asia it is quite as common as it is in Europe, and there its range seems to extend from Siberia to Southern China and Japan. It is likewise abundant in North America, extending from the north of that continent to the southern provinces of the United States. In early spring these birds always make their appearance in pairs, but towards the autumn large parties of them may be seen together, consisting of fifty or sixty individuals, who keep company with each other during their migration southwards. In their migrations it is generally understood that these birds only travel by night, and that wherever large lakes or rivers are to be found, as also along the sea-coast, they make their way principally by swimming. During the summer season the Crested Grebe takes up its abode on extensive lakes, where reeds and other water-plants are abundant. Their powers of swimming and diving are quite wonderful. According to Naumann's observations, this[Pg 243] Grebe will dive in the course of half a minute to a distance of two hundred feet. Its flight, too, when it thinks proper to take wing, is tolerably swift; it always proceeds in a straight line, and the whirring noise made by the rapid motion of its wings is audible at some distance. In its behaviour it seems to be the most circumspect and the shyest member of the family, and is not easily approached, more especially as it generally keeps in open water, where it can see to a distance. If surprised when in the vicinity of a bed of reeds, it immediately takes refuge among them, but only so long as to enable it again to plunge into deep water; if pursued it immediately dives, and when it comes up again to breathe, allows only its beak to appear above the surface, and as soon as it has taken breath dives again, until it has placed itself quite beyond the reach of danger.