PODICIPIDH, GREBES. 335 
Var. paciricus. Colors the same; size less; length about 2 feet; wing about 
11; tarsus 23; bill 2-21, very weak and slender. Northwestern Am., abundant 
on the Pacific Coast of the U.S. in winter. Lawr. in Bp., 889; Cours, J. c. 228. 
Rted-throated Diver. Blackish ; below white, dark along the sides and on 
the vent and crissum; most of head and fore neck bluish-gray, the throat 
with a large chestnut patch; hind neck sharply streaked with white on a 
blackish ground ; bill black. Young have not these marks on the head and 
neck, but a profusion of small, sharp, circular or oval white spots on the back. 
Size of the last, or rather less, N. Am. and N. Europe, common; dispersed 
over most of the U.S. in winter. Sw. and Ricn., F. B.-A. ii, 476; Nurr., 
ii, 519; Aup., vii, 299, pl. 478; Lawr. in Bp., 890.. | sEPTENTRIONALIS. 
Family PODICIPIDA:. Grebes. 
Bill of much the same character as that of loons, but generally weaker, in one 
genus only- quite stout and somewhat hooked. Nostrils linear, linear-oblong or 
oval, not lobed. Head incompletely feathered, with definitely naked lores, the 
feathers not reaching the nostrils; commonly adorned in the breeding season with 
lengthened gayly-colored crests, ruffs, or ear-tufts. Back not spotted; under 
plumage peculiarly silky and lustrous, usually white. Wings very short and con- 
cave, the primaries often attenuated at the end, covered by the large inner quills 
when closed. Tail a mere tuft of downy feathers, without perfectly formed rectrices. 
Feet lobate, the front toes also semipalmate; tarsi compressed, scutellate, their 
hinder edge rough with a double row of protuberant scales; toes flattened; claws 
short, broad, flat, obtuse, something like human nails. 
The grebes are strongly marked by the foregoing characters, especially of the 
feet and tail, though they agree closely with the loons in general structure and 
economy. Principal internal characters are the absence, it is said, of one carotid, 
the greater number of cervical vertebrae (19 instead of 13) and shortness of the 
sternum, with lateral processes reaching beyond the transverse main part (the 
reverse of the case in loons). The gizzard has a special pyloric sac. These birds 
are expert divers, and have the curious habit of sinking back quietly into the water 
when alarmed, like anhingas. Owing to the virtual absence of the tail the general 
aspect is singular, rendered still more so by the almost grotesque parti-colored ruffs 
and crests that most species possess. These ornaments are very transient; old 
birds in winter, and the young, are very different from the adults in breeding attire. 
The eggs are more numerous than in other pygopodous birds, frequently numbering 
6-8 ; elliptical, of a pale or whitish color, unvariegated ; commonly covered with 
chalky substance. The nest is formed of matted vegetation, close to the water, or 
even, it is said, floating among aquatic plants; the young swim directly. Grebes 
are the only cosmopolitan birds of the order, being abundantly distributed over the 
lakes and rivers of all parts of the world, though they are less maritime than 
the species of either of the other families. There are not over twenty well deter- 
mined species, for which fifteen generic, and about seventy specific, names are 
recorded. The genera requiring recognition are only two. In Podilymbus, the bill 
is short, stout, and bent at the end, the lores are broadly naked, the frontal feathers 
are bristly and there are no ruffs or crests; in all the rest of the grebes the bill is 
slender, straight and more or less acutely paragnathous, the naked loral strip 
is narrow, and the soft feathers of the head form lengthened tufts of various kinds. 
