318 Sketches of Some Common Birds. 



The cavity for the eggs is from five to six inches across, 

 and is comparatively shallow, being rarely more than an 

 inch and one-half deep. Attached to the broad rim of the 

 mound, like entangled raveling from the material in the 

 mass, there is from a pint to a quart of loose, shred-like, 

 blackened material, which is used by the female in cover- 

 ing the eggs in her absence. The mound is made of grass, 

 flag stems, moss, and mud, all in a soaked, decayed condi- 

 tion, interwoven with the roots and subterranean portions 

 of the stems amid which it is anchored. Few that I 

 have examined would float easily if detached from their 

 surroundings. 



An interesting feature of the incubation of this grebe is 

 seen in the fact that the female covers the eggs when she 

 leaves them for a time, unless she is completely surprised 

 on the nest and forced to leave so hurriedly that she can 

 not take time to place her home in order. However, I 

 have never been able to surprise one on her nest, though 

 other bird-seekers have been more fortunate. Some writers 

 assert that this grebe covers her eggs by day, and de- 

 pends upon the combined heat of the sun and the decora- 

 position of the matter in the soggy mound to keep up 

 their temperature, the bird incubating only at night. The 

 fact, however, proved by accurate observation of the birds 

 in their breeding resorts, is that the female patiently 

 broods her eggs by day as well as by night. She sits 

 closely on her eggs, seldom leaving them to take food, and 

 the covering material is so disposed that it can be hastily 

 scratched over the eggs almost by one motion of her short 

 legs. I have found many nests over which the shreddy 

 covering had been thus hastily thrown, for one or more of 

 the eggs were partially exposed. Complements in nests I 

 have examined varied from five to nine, and even larger 

 sets are recorded. The eggs are bluish white when fresh, 

 but contact with the nest often tinges them with yellowish- 

 brown stains. Frequently the eggs are more or less 

 thickly covered with a limy or chalky granular coating, 

 which obscures the ground-color. Davie gives the average 

 size of the eggs of this grebe as 1.72 by 1.17, in inches. The 

 breeding season extends until the latter part of June in ex- 

 ceptional instances. 



