Almost all the Waders are powerful Birds on the wing, and twice a year most of them emigrate like the Wild Ducks, Geese and Swans. There are exceptions to this rule, however. Some of them, like the Bustard, move through the air with difficulty; while the short winged species are unable to fly at all, their wings being only useful for helping them along in running, and thus assisted, they are remarkably swift. The nature of their food varies with the form and strength of the bill, and the locality they inhabit. It consists generally of Fish, worms and insects, and sometimes of small animals and reptiles, as well as grasses and seeds. The Waders are usually divided into six great families. These are classified under long Latin names descriptive of some peculiarity belonging to each, but which can be more easily remembered as: First, the Waders with united toes; second, the long-toed Waders; third, the Waders with long bills; fourth, the Waders with knife-shaped bills; fifth, the Waders with compressed bills; sixth, the short-winged Birds. THE WADERS WITH UNITED TOES. As the feet of these Birds are partly webbed, they seem to belong to the swimmers, but the arrangement of their toes is altogether different, and their unusually long legs would also place them in a different family. This is the smallest of the family of Waders. In fact only two varieties are usually found in it—the Avocet and the Stilt Bird. THE AVOCET. This Bird has a very curious bill—long, slender, flexible and curved upwards. It uses this strange instrument to rake up the sand and mud in order to catch the worms, small molluscs and Fish-spawn, which constitute its chief food. Its long legs enable it to travel in safety over swamps and lagoons; it also swims with great ease. It may often be seen looking for its food on the margins of lakes and ponds. The Avocet stands about twenty inches in height, although its body is but little larger than a Pigeon’s. It is a pretty bird, of slender make; its plumage is black on the head and back, and white underneath. It is to be met with on both the Continents; the European species is common in Holland and on the French coast. Wild and shy in its nature, it is very difficult of approach, and is clever in avoiding snares and in escaping pursuit, either by flight or swimming. The nest of the Avocet is a very simple structure, generally made by placing a few blades of grass in a hole in the sand, where it lays two or three eggs, of which it is frequently robbed, for they are regarded as great delicacies. The flesh, however, is of little value. THE STILT BIRDS.