BATHING WHILE FLYING Watching swifts or swallows coursing low over the surface of a lake and occasionally touching it leaves one with the impression sometimes that the birds are bathing rather than picking up insect food or drinking. With some other birds the habit of bathing from the wing is more definite. Sometimes drongo shrikes that are sitting up on a perch near the edge of a pool will fly out over the water, drop directly into it with a little splash, and then rise and fly back to their perch, where they either repeat the performance or sit and preen their feathers. POST-PRANDIAL ABLUTIONS Ospreys have been recorded as bathing while on the wing in a rather striking manner. They have been seen flying along just above the surface of the water, then descending into it, adopting a sort of vertical American-eagle attitude while flapping the wings, then rising a little, flying on, and repeating the process. It has been suggested that the osprey is washing its feet in this manner after finishing its meal. One observer makes this still more definite. He says that the osprey finishes its meal of fish on a perch in a tree and then flies low over the lake. Dropping both its legs, the osprey drags them through the water, flapping its wings all the time. Then it immerses its beak and head into the water while still flying along, apparently washing off the scales and slime that it had gotten on itself while making its meal of fish. HOW BIRDS ANOINT THEIR FEATHERS [Illustration] A bird's plumage receives a great deal of care from the bird that wears it. The bill is the only implement for this grooming, and it is run through and along the feathers it can reach, helping clean them and making sure they lie in their proper place in the bird's dress. There are parts of the plumage that the bird's bill obviously can't reach, as that of the head, but ducks at least surmount this difficulty by rubbing their head against their body. Many birds have oil glands (the only external glands that most birds have), a pair of glands just above and in front of the root of the tail, on the back. They contain an oily substance, and the usual explanation of its use is that the secretion of these glands is used in dressing the feathers. Certainly birds that have oil glands seem to use them, nibbling at them as though to press out the oil, touching them with the bill, and then rubbing the bill through the feathers, and rubbing the head against the oil gland. The beautiful, soft, whitish bloom seen on some birds' feathers, such as the pale gray of a male marsh hawk and filmy appearance of some herons' plumage, is caused by specialized feathers called "powder down." Sometimes this powder down is scattered through the plumage; sometimes it is in patches, such as the particularly conspicuous ones in the herons. The tips of the powder down are continually breaking off and sifting over the rest of the plumage, giving it the bloom that with handling quickly rubs off.