22 BULLETIN 107, UNITED STATES NATIONAL MUSEUM. 



cation much easier. The horned grebe covers its eggs when it leaves 

 them, but incubates regularly ; it is not particularly shy and has been 

 photographed on its nest; it is not easily driven from the vicinity 

 of its nest, and will soon return to it if given a good chance. 



Eggs.—Th.& eggs of the horned grebe are absolutely indistinguish- 

 able from those of either the eared or the pied-billed grebes. In shape 

 they vary from " elliptical ovate " to " elliptical oval." The shell is 

 fairly smooth with very little luster. The ground color is dull 

 bluish white or pale olive white, which is generally more or less, and 

 often wholly, concealed by a deposit of mud and dirt or by nest 

 stains which will not disappear with washing. The set usually con- 

 sists of 4 or 5 eggs, but sometimes 3 eggs are incubated and some- 

 times as many as 9 or 10 are found in a nest; perhaps these large 

 sets are laid by more than one bird. If only one brood is raised in 

 a season, there is a great variation in the dates, but Dr. P. L. Hatch 

 (1892) has suggested that as the young "have been seen swimming 

 with the parent as early as the first week in May, and at the ten- 

 derest age as late as the 3d of August," there may be two broods 

 raised occasionally. The measurements of 45 eggs, in the United 

 States National Museum and the author's collections, average 44 

 by 30 millimeters ; the eggs showing the four extremes measure 47.5 

 by 29.5, 46 by 31.5, 40 by 29 and 43 by 28 millimeters. 



Plwnages. — The downy young is almost black above, striped and 

 spotted with grayish white; there is a median white stripe on the 

 occiput and a white V on the forehead, extending down the sides of 

 the neck in broad irregular stripes ; the sides of the head, neck, and 

 throat are white tinged with " salmon buff " and spotted with dusky ; 

 the under parts are white and the sides dusky. The young can swim 

 and dive like experts soon after they are hatched. They develop 

 rapidly and soon acquire the juvenal or first plumage, which is worn 

 through the late summer and into the fall; it is similar to the first 

 winter plumage, but is characterized by the dusky stripes and spots 

 on the sides of the head and throat. These dusky markings disappear 

 during the fall and the young birds become similar to the adults. 

 Young birds in the first winter can be distinguished by the light 

 edgings of the feathers of the backs, by the lighter and browner 

 plumage in the crowns, and by the smaller or lighter colored bills; 

 adults have clear black crowns, the cheeks are usually purer white, 

 the plumage of the heads is more fluffy, and the biUs are larger and 

 blacker. The prenuptial molt apparently includes the entire head 

 and body plumage, and young birds are indistinguishable from adults 

 after the first spring. The spring molt usually occurs in April, 

 sometimes a little earlier or later, but it is usually completed before 

 the middle of May. Birds in full nuptial plumage have been taken 



