106 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



Meyer found that the size of the nests at the Duck Islands varied 

 greatly. He writes : 



The average of seven nests was : Outer diameter, 15 inches ; inner diameter, 

 8 inches; depth outside, 4J inches; depth inside, 31 inches. One nest in the 

 heavy timber measured 22 by 8 by 6 by 5. One of the tree nests was 28 inches 

 in diameter. 



Eggs. — Only one brood is raised, but when the nests are frequently 

 robbed the birds are kept laying all summer. Three eggs constitute 

 a set, although the number is sometimes only two, and in very rare 

 cases one or four. The color of the eggs varies within wide limits. 

 Dutcher and Bailey, from an examination of many hundreds at 

 Duck Island, Maine, found that : 



The ground colors were light sky blue, dead blue, light blue-gray, light gray- 

 blue, dark lilac-gray, light gray, light pea-green, green drab, warm drab, ocher 

 drab, pink drab, light brown, and cinnamon. The colors of the markings were choc- 

 olate brown, rich brown, light brown, snuff brown, asphalt, black, lilac, mauve. 

 The shape of markings was almost infinite — large and small spots, indistinct 

 specks, blotches, lines, and irregular streaks, somewhat like the markings on 

 the eggs of blackbirds. One egg was found with a light sky-blue ground color 

 with tiny indistinct specks of lilac and light brown. Some of the markings 

 were so confluent that they resulted in a distinct line around the egg. 



Major G. Ralph Meyer writes : , 



The eggs varied greatly in shape, size, and color. Eggs were found varying 

 from short ovate to cylindrical ovate. The most common shape was the 

 elongate ovate. 



The measurements of 45 eggs, in the United States National 

 Museum and by Major Meyer, average 72.3 by 50.5 millimeters ; the 

 eggs showing the four extremes measure 82 by 52, 74.5 by 53 and 

 58 by 45 millimeters. 



Young. — The period of incubation varies from 24 to 28 days, the 

 average being 26 days. Dutcher and Bailey found an interval of 

 about 12 hours between the hatching of each egg. Dutcher and 

 Bailey (1903) show conclusively that in some cases at least both 

 sexes incubate. They say: 



It was also observed that as the period of incubation neared its end the 

 anxiety of the parents increased in a marked degree, so that it was easy to 

 determine the stage of incubation by the action of the parents. During the last 

 few hours, before the pipping and cracking of the egg, the parent birds were so- 

 fearless that they would leave the nest only on a near approach. 



Several observers have found that the eggs were turned slightly by 

 the bird's bill, feet, and breast. The mate of the sitting bird is often 

 stationed near at hand. 



The young are soon on their feet after leaving the egg, and, accord- 

 ing to Dutcher and Bailey, " the instinct to hide seems to be developed 

 within an hour or two after hatching." They conceal themselves or 

 sometimes only push their heads under pieces of wood or projecting 

 rocks or in the grass. The object of this habit may be also a desire 



