Water, shore and predatory birds

Water birds spend much of their life in water. They have webbing between the toes and legs set far back, so they swim and dive well but walk slowly and clumsily on land. Dense feathers and down make a waterproof layer; the bird squeezes oily fluid from the preen gland with its beak and spreads it on its feathers, so they do not get wet. That is why a water bird does not chill in water, while a hen that falls in has soaked feathers and gets cold. The order of waterfowl includes ducks, geese and swans: the beak edges carry horny plates and the tip is widened; the chicks are precocial and follow the mother. A duck strains mud through the plates in its beak and separates small animals and plants. The mallard, garganey and pintail live in Central Asian water bodies; the mallard is the ancestor of the domestic duck. Geese are larger than ducks, eat plants, and the male and female look alike; the greylag goose, ancestor of the domestic goose, nests at the lower Amu Darya. Penguins have short wings turned into flippers and legs set at the back, so they stand upright on land; they eat fish and crustaceans and live in the southern hemisphere. The emperor penguin is a little over 1 m tall and incubates its egg in the extreme cold of the Antarctic winter. Shore birds feed in shallows and marshes, have long necks and legs, and do not swim. The white stork is large with a long beak and legs; it eats frogs, mice, insects and lizards, and nests in trees or on building roofs. It is useful and protected because it has declined.