170 BULLETIN 16 7, UNITED STATES NATIONAL MUSEUM 



millimeters; the eggs showing the four extremes measure 64.5 by 

 48.3, 61.5 by 49.6, and 53 by 43.5 millimeters. 



Young. — Incubation lasts for 28 days and is shared by both sexes. 

 Bendire (1892) says that "the eggs are deposited at intervals of a 

 couple of days." Both parents assist in the care of the young, which 

 remain in the nest for about six weeks. In the nest that Mr. Finley 

 (1905) studied the young were hatched on April 20 and they left 

 the nest on the first" of June. 



Mrs. Irene G. Wheelock (1904) tells the following remarkable 

 story of a young hawk that was tlirown out from a nest and fluttered 

 helplessly to the ground : 



It fluttered about on the grass, and after resting a time managed to scramble 

 into a low bush, where it felt more secure, though it reaUy was much more 

 exposed. In the meantime the adults had circled wildly about with discordant 

 screams, and the mother still remained near. Curious to see how. she would 

 manage to get that unlucky youngster back into his nest, we moved off fifty 

 yards and watched tlirough the glasses. Both parents swooped down and looked 

 at him, from on the wing, again and again, screaming when away, but silent 

 whenever near him or the nest. At length a more sudden swoop and a momen- 

 tary flutter, as a butterfly flutters over a flower. Then she rose carefully and 

 slowly, with the young in her claws, and carried him to the nest. It was 

 impossible to see whether she was holding liim between them or grasping him 

 by them. 



Mr. Sumner, in his notes, thus describes the departure of a young 

 bird from its nest : 



One bii'd, when frightened, walked to the edge of the nest and facing tlie 

 breeze spread his wings and then, half balancing, walked out on a small dead 

 branch until 4 feet from the nest, where he remained, now with folded wings, 

 quite at ease, although swaying in the wind. All at once the brancli broke 

 under his weight, whereupon he sprang into the air with vigorously flapping 

 wings and flew partly against, partly beaten back and buoyed up by, the wind 

 for 100 feet. He lit on the slough bank, stayed there a moment, and then, of 

 his own accord, jumped off and flapped low over the water across the slough 

 and lit again on the other side. Presently he began to run, head low, wings 

 partly unfolded, in typical hawk fashion, always putting distance between him- 

 self and me. Presently he squatted down, in the same prone position as in the 

 nest — a move that may well be one of self protection, and here he stayed, even 

 though I hid beneath a dead tree limb 100 feet away, with his eyes flxed on me, 

 until after 15 minutes I got tired and left. 



Leslie L. Haskin says in his notes that these young hawks "are the 

 noisiest of all young land birds. This is especially true just after 

 they have left the nest. They follow the old ones around at feeding 

 time — which seems to be all the time that it is light — screaminor at 

 the tops of their voices. Two or three young redtails hungrily fol- 

 lowing the old ones sound like the squalling of a litter of pigs. In 

 feeding the young birds the old hawk often mounts high in the air 



