If alarmed when with its young, the Picapare at once takes wing, and betakes itself to the shelter of the thick bushes that cover the shore; if still further pressed it hides among rushes and reeds until the danger is passed. It seems only to dive when seriously alarmed, as for example, when shot at; on such occasions it will remain under water for a considerable space of time; its powers of diving, however, are far inferior to those of many water birds. [Illustration: THE STILT BIRD (_Charadrius himantopus_).] THE SWIMMERS (_Natatores_). BUT little difference of opinion exists among naturalists as to the limits of our last order; indeed, a swimming bird is at once recognisable by characters so sharply defined that there is scarcely room for doubt or hesitation. The grand character whereby they are all distinguishable is to be found in the structure of their feet, the toes of which are more or less completely united to each other by a broad web by which they are converted into paddles, admirably adapted to propel them through their appropriate element. Hence they swim with facility, and frequent rivers, lakes, and seas. Generally speaking, the _Natatores_ move awkwardly on land, as, in order to render the strokes of their paddle-like feet more effective, their legs are placed more or less behind the centre of gravity, so that when on the ground they have, in a great measure, to retain their balance by muscular exertion, as may be seen in the Goose or Swan as they waddle clumsily over the grass. In some cases these birds are compelled to assume an upright attitude, as do the Auks and Penguins. In the structure of the feet important differences are observable, generally only the three front toes are connected together by the web, but occasionally the hind toe is likewise included in the expansion of the skin, or is provided with lateral appendages that materially enlarge its surface. The form of the body in the swimming birds is boat-like; in those that dive, the ribs are strong and carried back, so as to almost entirely surround the enclosed viscera, and thus defend them from undue pressure. Their plumage is dense, close, and waterproof, consisting of a thick under garment of down overlaid with broad flat feathers, which throw off the water as if their surface were oiled. In many groups the neck is very long and the tail very short, while in others the tail composed of rigid quills is employed as a rudder when the birds are diving. Some are utterly incapable of flight, and use their wings in the water as though they were fins. The members of this order live almost exclusively upon animal food, only a few preferring a vegetable diet. All, without exception, are sociable in their habits; most of them exceedingly prolific, some species, however, lay but one egg. Frequently they crowd their favourite breeding-places in great numbers, and are devotedly attached to their offspring; some will even incubate eggs, and rear young that are not their