82 BULLETIN 16 7, UNITED STATES NATIONAL MUSEUM 



as only one chick hatched and it promptly ran away. Perhaps the 

 hawk's nest had been destroyed and she adopted the nearest available 

 nest. 



Eggs. — Perhaps the commonest number of eggs is five, but four 

 or six are frequently found and occasionally as many as seven 

 or eight, or even nine, are seen in a marsh hawk's nest. In shape 

 they are ovate, short-ovate, or nearly oval. The shell is smooth, 

 with little or no gloss. The color is dull white or very pale bluish 

 white. They are generally unmarked, but about 10 percent of 

 the sets show, more or less, scattered spots of very pale browns, 

 "cinnamon-buff" or paler, dull buff. The measurements of 84 eggs 

 average 46.6 by 36.4 millimeters; the eggs showing the four extremes 

 measure 53 by 38, 48 by 39.5, 41.4 by 35.6, and 43 by 34 millimeters. 



Young. — The period of incubation has been variously estimated 

 as 21 to 31 days; the latter figure was definitely noted by Aretas 

 A. Saunders (1913). It is difficult to determine, as it often begins 

 when the first egg is laid ; an egg is usually laid each day, but often 

 a day or two may intervene between layings. Both sexes share 

 the duties of incubation and care of the young, and they are very 

 devoted parents. Mrs. Irene G. Wheelock (1904) writes: 



In eigbteen to twenty days the young Hawks break their hard shells, one 

 each day, and cuddle down among the feathers and straw of the crude nest. 

 From the day the first little ball of down appears, one or the other of the 

 adults may be seen constantly on the wing over that meadow. The same 

 tactics are pursued as before, for the food is dropped to the parent on the 

 nest, who, after the first few days, holds it fast in her beak while the 

 nestlings tear off bits from it for themselves. In this way the muscles of 

 the bill and neck are developed. Later on the food is simply dropped to 

 them, both parents being off on the hunt, and the little fellows grasp it 

 in their sharp claws and tear from it with a right good-will. 



Aretas A. Saunders (1913) noted that three eggs in a set of 

 five hatched between the evening of June 30 and the morning of 

 July 1. The fourth bird hatched before the morning of July 2, 

 the fifth on the afternoon of July 4, and the sixth on July 7. He 

 noted that thej'- were born with their eyes closed, but that they opened 

 within a few hours. Following is his account of their development : 



For the first six or seven days the young showed no change in appearance 

 except that they grew larger and became somewhat more active. On July 8, 

 ju.st after the youngest bird had hatched, I noted that the oldest birds were 

 about three times the size of the youngest. About July 10 the two youngest 

 birds disappeared, probably having died. I believed that this was because they 

 were so much smaller and weaker than the four older birds that they were 

 unable to get their proper share of food. 



Sheathed feathers began to appear in the oldest birds at the tips of the 

 wings on July 8, when they were seven day.s old. On July 14, when twelve 

 and thirteen days old, the birds began showing fear and crawled back into 

 the cinquefoil bushes when I approached. When I attempted to handle them, 



