Heidi Fosback, age 10, of Spokane, Wash., for her question:

WHY DO BIRDS TAKE DUST BATHS?

Most of us visualize birds as graceful, soaring, freedom loving creatures who glide through life with very few problems. Of course, we know they often scrounge for food, fight over territory and fall victim to predators. What may surprise us, however, is the trials and tribulations birds suffer at the hands of ever present, bothersome parasites. These ectoparasites infest a bird's external body parts, and include such pests as lice, fleas, various flies, mosquitos, ticks and mites.

Birds frequently groom themselves and each other to help get rid of these damaging insects. Water baths, besides being refreshing, help, too. And a good flap in the dust, allowing the dry, powdery soil to thoroughly penetrate the feathers, no doubt does its part in suffocating many unwanted guests.