66 NATURAL HISTORY OF BIRDS. 



long legs and feet, features which none of them share. The grebes have only lobate 

 feet, like the phalaropes and the gallinules, which, however, have well-developed rec- 

 trices, not possessed by the grebes. 



The grebes already in their external appearance manifest aberrant characters, 

 which secure for them a separate position as COLYMBOIDE^E (with exclusion of the 

 loons, the Urinatoridre, which, though having some general resemblance to the former, 

 differ in many very essential points). The grebes have no supraorbital depression for 

 the nasal glands; the number of cervical vertebra? (15 to 19) is unusually large; the 

 sternum is quite different, the xiphoid process being shorter than the lateral ones, and 

 notched behind ; the pelvis is also singularly long and narrow, and the diverging pubic 

 bones rather peculiar; the ambiens muscle is absent, and the formula of the leg 

 muscles is BX, while in the loons the ambiens is present and the formula is ABX ; 

 only one carotid is present; the primaries are eleven, a very unusual number; true 

 rectrices are absent ; the toes are lobate. In all these and several other features do 

 they differ from the loons, with Avhich they share the long cnemial process of the 

 tibia in front of the knee. The head is, in a good many species, most singularly 

 adorned during the breeding season by bright-colored ruffs and crests, which give 

 the birds a very odd appearance, still further increased by the broad, flattened 

 toes, and the total absence of an external tail. The grebes look extremely old- 

 fashioned; that is, they impress iis as if their grotesque figures were only survivors 

 from by-gone periods, which we are used to imagine populated by all sorts of fanciful 

 creatures. 



Only one family, COLYMBID^E, also known as Podicipidse, with about thirty species 

 referable to a few genera, composes at present this superfamily. As a group they are 

 nearly cosmopolitan, though mainly confined to the temperate regions of both hemi- 

 spheres. Their habits present many strange features quite in keeping with their curi- 

 ous aspect. They are among the most expert divers, but, in contradistinction to the 

 penguins, never use the wing in diving, the large, curiously-shaped feet performing 

 the propulsion alone. The extreme compression of the tarsus, to use Macgillivray's 

 words, and the arrangement of the toes, enable the feet to be brought forward with- 

 out receiving almost any opposition from the water, and in giving the propelling 

 stroke, the blade, thus folded up, is expanded into a broad, lobate paddle. Among 

 flying birds none are so completely water birds as are the gi'ebes. They very seldom 

 leave the water, and must be pressed very hard before they take to the wing; nothing 

 but the direst necessity will force them on land, for not only do they feed entirely on 

 the products of, and in, the water, but they sleep and even breed on the surface of 

 that element. Their nests ai - e floating masses of wet vegetable material, Avhich the 



^j O 



parents secure by diving ; this swimming abode, which they anchor to some reed or 

 grass, is sometimes constructed over deep water, and the eggs are often hatched when 

 partly lying in the water. When out of the shell, the young has not far to walk; he 

 looks a few moments over the edge of his water-drenched cradle, and down lie goes 

 with the expertness of an old diver. The grebes have a peculiar faculty of regulating 

 their floating in the water ; usually they lie quite high, but if alarmed, and fearing 

 danger, they can press themselves down under the surface, so that only the long, thin 

 neck and the back of their flat body is visible above. They 'feed chiefly upon fishes, 

 and may, therefore, in some localities, become injurious. Their skin, with the peculiar 

 silky feathers, is in great demand for trimmings, ladies' hats, muffs, etc. 



The grebes are migratory in the colder parts of their range, and spend the breed- 



