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 120 THE CONDOR Vol. XIX 115 degrees, although a good breeze may bring the general temperature down to a hundred degrees. How comfortable for the young birds to move out to the edge of the nest ! Here they usually sit in a row facing in and towards the wind if there is any. Before they are large enough to do this, they must of necessity remain in the shade of the half-raised wings of the mother, who remains on the nest to shelter them for at least two weeks, and at intervals for a week longer, after the incubating period. The whole osprey family might serve as a model of deportment. While the mother is busy brooding the eggs, her mate is away fishing for her; when he brings in her fish, as he does at quite regular inter- vals, he tears it up and gives it to her in small pieces. Later he redoubles his activities and brings in trout for both the nestlings and their mother. One morning I came in sight of a nest containing three young birds. The female was on the nest with her back to the sun and her wings drooping slight ly. Just in front of her breast in the shade were her babies, each clad in light brown down that could barely be made out against the floor of the nest. The father was on a dead pine a quarter of a mile away, with a fish from which he had removed the head and entrails. Soon two or three shrill whistles were sounded by the female, which proved to be the food call; for the male dropped down to the nest immediately thereafter. The mother stood up and the four- day-old youngsters arranged themselves in an orderly row; no attempt what- ever was made to get to the fish although it was only three inches from their bills. The male stood on the fish (a trout of about one pound weight) and tore it up, giving it bit by bit to the mother, and occasionally a tiny bit to a nest- ling. It was the mother, however, that did most of the feeding. She received the fish in pieces not larger than half an inch in diameter, reduced them to still smaller size, and fed each bird in turn until all were satisfied. Then the mother ate the remainder, and I believe the bones and skin were also onsumed. The male flew back to*his stub to preen while the mother settled down once more to shelter her young. The whole scene from the first food call at eight o'clock lasted only half an hour. At a later date I observed that the fish was occasion- ally turned over entire to the female. The careful training that young ospreys receive is further shown when a nest is approached. On hearing the whistled alarm given by a parent, usually the mother, the young birds throw themselves fiat on the floor of the nest often with necks and wings outstretched. When the observer reaches the nest no movement is to be seen; the nestlings permit one to take them up, turn them over, or place them in any position without offering any sign of life beyond the half-open, staring eyes. After the nest is left, the young ospreys maintain their position until the parents have given the reassuring signal. I have seen half-grown ospreys hold this inert posture for an hour and twenty minutes while the parents were fiying about or even standing on the edge of the nest, but no motion whatever was made until the proper signal was sounded. Young ospreys are not fast growers, but at ten days of age begin to show black on the primaries; and ten days later, more distinctive markings commence to appear. From thirty-five to forty-five days after hatching they leave the nests fully leathered and strong of wing. Only once in my experience have I seen ospreys fight among themselves and that was due to disputed ownership of a trout. In the Yellowstone, at least, the ospreys live in perfect harmony with smaller birds. An impressive instance was to see a bird plunge into a creek within a few feet of a two-week