Page:Life Histories of North American Diving Birds.djvu/32

 chick on her back even if it is not visible, because she generally swims higher in the water.

As I was lying low in the reeds, another pair of grebes swam past. The back of the one bird was high out of the water. She was carrying two young, but at the time neither was visible. But soon one of the youngsters got anxious to crawl out on the hurricane deck, as it were. Each time his head appeared, the mother would reach back and cover him up. Finally one of the little fellows crawled clear out in full view and she let him sit there for a moment. But I could see this was not the customary way of riding, for she soon raised her wing and covered him. Occasionally she picked up bits of something from the surface and reaching back fed her babies. A little later, while the father was swimming near by, I saw one chick slip off the mother's back and go paddling toward him. He seemed to lower his body slightly in the water and the youngster floated aboard.

The old grebes dive and swim readily under water with the young on their backs, but occasionally when they are frightened they lose their chicks. Several times while we were rowing about the lake we came unexpectedly upon old grebes carrying young. At such times, when the old birds are scared, it seems very difficult for them to hold the chicks in place when they dive. In most cases the young birds come to the top of the water after the mother dives. When we approached the little fellows they tried to dive, but could not stay under long or go very deep, so they were easily caught.

Plumages.—The downy young of the western grebe is entirely different from the young of any other American grebe; its plain, unspotted coat suggests a closer relationship with the loons than with the other grebes. It is covered with short, thick down, as soft and smooth as silk velvet. The upper parts are "light mouse gray" in color, darkest on the back, lighter on the crown and shading off to "pallid mouse gray" on the neck and sides and almost to pure white on the belly; there is a triangular naked spot on the crown. The young grebe retains its soft downy covering as it increases in size, and it is nearly fully grown before its first real plumage is assumed. There is no distinctive juvenal plumage, and the first winter plumage is not strikingly different from that of the adult. The young bird in the fall is dark gray or dusky instead of black on the crown and hind neck; the line of demarcation is not so sharply drawn between the dark crown and the white throat, and the feathers of the back are edged with grayish white. A partial prenuptial molt in the spring produces the black crown of the nuptial plumage and the light edgings on the back disappear by wear. In this first nuptial plumage adults and young are practically indistinguishable.

The seasonal changes of the adult are not conspicuous, for the fall plumage is much like the nuptial plumage; the black of the crown is duller and less clearly defined in the fall. There is a complete post-nuptial molt in July and August, during which the wing quills are all shed simultaneously and the bird becomes incapable of flight. A partial prenuptial molt, involving mainly the head and neck, produces the nuptial plumage.