258 BIRDS OF ILLINOIS. 



FAMJLY PODICIPIDJE. THE GREBES. 



CHAKACTEBS. Swimmers resembling the Loons in the posterior insertion of the legs, 

 but the toes lobate and semipalmate, instead of completely webbed, the claws broa-J, flat, 

 avd nail-like, instead of normally narrow and curved. Bill variable in shape; nostrils vari- 

 able, but without an overhanging lobe; wings very short and concave, the primaries cov- 

 ered by the secondaries in the closed wing; tail rudimentary, consisting of a mere tuft of 

 downy, loose-webbed feathers, without perfectly formed rectrices; plumage of the lower 

 surface remarkably silky and lustrous, usually white. 



The Grebes are aquatic birds, poorly adapted for protracted 

 flight, on account of the smallness of their wings, but among 

 the most expert of divers. Their nest is a thick matted plat- 

 form of rushes, sedges, etc., usually floating upon the surface of 

 the water in grahsy or sedgy ponds or marshes. The eggs are 

 2-5, dull white, bluish white, or very pale bluish green, usually 

 stained more or less (often quite deeply) with light brown, by 

 contact with decomposed vegetable matter. 



The recognized North American genera may be distinguished 

 as follows: 



A. Bill slender, the length of the culmen much more than twice the depth of the bill at the 



base. 



[1. .ZEchmophoi us. Length of culmen at least five times the greatest depth of the bill; 

 neck nearly as long as the body. (Not represented in the Illinois fauna.)] 



2. Colymbns. Length of culmen less than four times the greatest depth of the bill; 



neck much shorter than the body. 



B. Bill very stout, the length of the culmen less than twice the greatest depth of the bill 



3. Fodilymbos. 



GENUS COLYMBUS LINN^US. 



Colymbus LINN. S. N. ed. 10, i. 1758, 135; ed. 12, i, 1766, 230. Type, by elimination, Colymbus 



cristatus LINN. 

 Podiceps LATH. Ind. Orn. ii, 1790, 780 (part; but, type, by elimination and restriction, Colym- 



bu* fluviatilis TUNST.). 

 J)ytes KAUP. Sk. Ent. Eur. Thierw. 1829, 49. Type, Colymbus cornutus GMEL.,=(7. auritus 



LINN. 



Proc.topus KAUP. L c. Type, Podiceps nigricottis BREHM. 

 Otodytes REICH. Syst. Nat. 1853, p. Ill (same type). 

 Tachybaptus RBICHENB. Syst. Av. 1852. p. iii. Type, Colymbus minor Gtfzij.,= CJluviatilis 



TUNST. 



GEN. CHAB. Neck much shorter than the body; bill not longer than the head, more or 

 less slender, its depth never more than one *hird the length of the culmen ; tarsus decidedly 

 shorter than middle toe with claw. Nuptial plumage ornamented by colored tufts, ruffs, or 

 patches about the head, and very different in this respect from the winter plumage. 



