PODICIPIDiE, GEEBES. 725 



. Family PODICIPID^ : Grebes. > 



Bill of variable leiijith, much longer or shorter than head; culmen nsnally about' 

 straight, soiiietimes a little concave, or quite convex, especially at the end. Commis- 

 sure nearly straight, but more or less corresponding with the curve of the cnlmen, 

 usually sinuate at base. Under outline of bill in general convex, with slight goiiydcal 

 angle or none. Sides of bill more or less striate. Nasal fossic well marked, the nostrils 

 near their termination. Nostrils linear and pervious (broader in Podihjmhns), upper 

 edge straight, not lobed. Frontal extension of feathers considei'able, and usually 

 anti;e run still farther into the nasal fossa. A groove along the symphysis of the man- 

 dible extends often nearly to tbe tip. Eyes far forward, with a loral strip of bare skin 

 running thence to base of upper mandible, very narrow in the typical forms, broader 

 in Tuchh/haptcs and rodiliimbiis. Head usually adorned in the breeding season with 

 variously lengthened colored crests or rufl's ; when these are wanting the frontal feath- 

 ers may bo bristly. Neck usually long, slender, and sinuous. Plumage thick and com- 

 pact, smoothly imbricated above, below of a peculiar smooth, satiny texture. Wings 

 short but ample, very concavo-convex ; primaries eleven* narrow, somewhat falcate, 

 graduated, the three or four outer ones attenuate on one or both webs; secondaries 

 short and broad; tertials very long, hiding the rest of the quills when the wing is 

 cloyed. Bastard quills unusually long, their tips reaching over half way to the ends 

 of the primaries. Greater coverts also very long. Tail rudimentary, represented by 

 a tuft of downy feathers. t Characters of the feet peculiar; for in other lobe-footed 

 birds, as I'halaropes and Coots, the lobation is of a difl'ercnt character. Tarsi exceed- 

 ingly compressed, with only a sligbtly thickened tract within which the tendons pass. 

 Fivout edge a single smooth row^ of overlapping, the liinder serrate, with a double row 

 of pointed scales; sides regularly transversely scutellate, as are the upper surfaces of 

 the toes, the latter being interiorly reticulate with an edging of pectinated scales. 

 Toes flattened out and further widened with broad lobes, especially wide toward the 

 end, and at base connected for a varying distance by iuterdigital webs. Hind too 

 highly elevated, broadly lol)ate, free. Claws short, broad, Hat, obtuse, of S(|uavisk 

 shape ; that of the hallux minute. Tarsus no longer or much shorter than the middle 

 toe and claw ; outer toe usually rather longer than the middle; the inner the shortest 

 of the anterior ones. 



This is a very natural group of numerous closely-related siiecies. Extremes of form 

 may be seen in Fodieepfi occidentalia and Fodilymhiis podiceps. There are but two strongly 

 marked genera, though many have been instituted. These genera, one of which has 

 several subdivisions, may bo deliued as follows, to iuclude all the subgenera found iu 

 North America : 



Analysis of North American [/en-jra and snhijriicra. 



A. Bill slender or only umdcratcly stout, paragnathous, acute. Nostrils 

 narrow or linear. Loral bare strip narrow. Frontal feathers normal. 

 Tarsus generally but little, if any, shorter than the middle toe — at 

 least Ihree-fourths as long. Semijialmation of toes moderate. 

 Lobe of hallux broad. Usually with conspicuous crests or rutt's 

 during the breeding season PODICKPS. 



1. Bill longer than head, extremely slender an 1 acute. Tardus 



equal to the middle toe and ciaw. Crests and ruffs slight. 



Ijarge j!Echmo2)horus, 



2. Bill not longer than head, moderately stotit. Tarsus shorter 



than juiddle toe and claw. Crests and rutl's decided. Size 



over 10 inches Podiceps^ 



3. Bill much shorter Ihan head, not two-thirds the tarsus, ([uito 



stout. Tnrsus about three-fourths the middle toe. (Jiiter 

 and middle toes eijual. No (h^cided crests en- rutls. Small; 

 length 10 inches or less Tachijhaples. 



* A greater number than have been shown to occur in other birds, with few excep- 

 tions. The same number is stated to occur among I'hasiiiiiida\ 



t''The tail of the (Jrebes is usually described as a small tuft of feathers, but on 

 carefnily removing the ioverls and downy parts the tail may \h' satisfactorily tiaced. 

 In tliis species [ v. erisUtlitf!'] there are feurtecn featheis ; on each side se\t'U, arranged in 

 a s(;micii('ular nuumer. Tlu- two middle feathers are separated to the distance of al)out 

 OEc-twclflh, and the two outer or lateial approac'h each otlier below, leaving an interval 

 of about the sanu^ space. When the fi^atiiers are broken across their bases, wliich they 

 frequently are, there is thus ])rodueed an appearance of a snuill circular tuft. W'lieu 

 lierl'ecf, tliey are about].! inches long, ami arched, with loose barbs, downy at their 

 extremity." {Andnhon.) 



