Robert Marches, age 8, of Westbury, Long Island. for his Question:
Why does water run off a duck's back?
The lily-white duck was adopted by the human family ages ago. HEr special
Chafe is the farmyard pond. Mrs. Duck spends a lot of time swimming and. diving in the water, and you would think that her feathers would be sopping wet. But her satiny coat is always dry; and. if you pour a glass of water on her back, it rolls down her sides in silvery raindrops.
The farmyard duck is. A water bird, and 45 of her water bird cousins Enjoy life in North America. Sane of her cousins are wild dunks with feathers freckled and speckled with browns. The wild drakes or papa ducks often wear patches of shimmering blue, green or yellow feathers. The wild and time geese and swans are also members of the duck family.
All these water birds are more at home in the water than they are on land. They have wide, webbed fret, which they use to row themselves through the water. But on land, their big, flat feet are clumsy, and the duck and her cousins must waddle along when they leave the water.
Naturally you wonder how a farmyard duck manages to keep herself dry. But there are really two mysteries about her, and when you solve one of her secrets you have solved them both. Maybe you have seen a snow-white duck beside a dirty dirty pond and warder how she keeps so clean. If you watch her a while, you will discover how she keeps clean and how she keeps dry.
When she leaves the water, she squats on the muddy shore and begins to preen herself. She uses her wide yellow bill to stroke her feathers this way and that each of her satiny white feathers is carefully stroked. This removes the dirt. But as she doe this, the duck also covers her feathers with a thin film of oil. And water, as we know, runs off an oily surface.
The duck has two special glands in her skin where the oil is made. They are way dawn on her back, dust above her tail. Watch haw often she touches this spot as she preens herself. Her bill squeezes out a little oil, and when it preens the next feathers, they get a thin coating of oil. When the preening job is done, the duck has her own raincoat to keep the water from soaking through her feathers.
All the waterfowl of the duck family preen themselves in the same way. They may do this five or six times a day. The waterproof raincoat is merely the outside layer of a waterfowl's feathers. It keeps them dry, but it does not keep her warm. Under the glossy raincoat is a soft layer of warm, downy feathers to keep her cozy even in chilly winter weather.