Vicki Hansen, age 12, of North St. Paul, Minnesota, for her question:

How do birds keep their feathers clean?

In Andy's garden there is a rocky little pond that the local birds use as a community bath. Usually they arrive at dawn and chatter noisily while they dip in and out, splashing the water on their claws, among their feathers and even under their wings. Andy's cat Rama knows that nobody loves him if he scares a bird, so he stays back and merely mutters his disapproval. Most birds like a shower now and then but when water is scarce they scuff through a patch of dry dirt and clean their feathers with a dust bath.

A bird's soft body feathers and stiff wing feathers must be clean and neatly combed to keep him warm and help him to fly. They also require a thin gloss of waterproof oil. Every day he must groom himself. His special brilliantine is manufactured by glands in his skin, maybe along his back or under his wings or tail. He uses his beak to prod out a helping of this oil and comb it through each and every feather. Sometimes he splashes up a shower of water to help with his primping and sometimes he takes a dry bath in the dust.