724 COLYMBUS SEPTENTEIONALIS, EED-THROATED DIVER. 



The feathers look as dry as if the bird had never been under water ; the 

 fish is swallowed head first, with a curious jerking motion, and tlie bird 

 again swims at ease, with the same gracelul curve of the neck. 



COLYMBUS SEPTENTRIONALIS, Linn. 

 Red-throated Diver. 



CoJi/nibua scptcrtirionalis, Lixx., Syst. Xat. i, 1766, 220 (adult).— Lath., Incl. Orn. ii, 1790, 

 801.— Temm., Man. iei5, 602.— BoiB, Isis, lfc:2-2, 561. — Steph., G. Z. xii, 18:4, 

 238.— Kkys. & Blas., Wirb. Eur. 1840, 91.— Gkay, Gen. of B. iii, 631.— Su^'o., 

 Svensk. Fo^l. pi. 5:?.- Bp., Syn. 1828, 421 ; List, 18:!8, 6.5.— Sw. & Eicii., F. B. 

 A. ii, 1831, 476.— NuTT., Man. ii, 16:j4, 519.— Ai;d., Oru. Biog. iii, 1835, 20, pi. 

 202; Svn. 1839, 3.54; B. Am. vii, 1844, 299, pi. 478.— Gjk., B. L. I. 1844, 380.— 

 Lawr.,' B. N. a. lf^.58, 590 ; Ann. Lye. X. Y. viii, lf^66, 300 (New York).— CouES, 

 Pr. Phila. Acad. 1862, 228.— Newt., Ibis, 1865, 317 (Spitzbergen).— Coop. & 

 Suck., N. H. Wash. Ter. 1860, 279.— Dall & Baxx., Tr. Chic. Acad, i, 1869, 307 

 (Alaska).— FiNSCH, Abh. Nat. iii, 1872, 75 (Alaska).- Tdrnb., B. E. Pa. 1869, 

 39 (rather rare). — CouES, Key, 1872, 335 ; and of authors generally. 

 Cepphis septentrionalis, Pali,., Zoog. Rosso- As. ii, 1811, 342. 



Eudijtes septentrionalis, III., Prod. 1811, 282.— Nauii., Vog. Deut. xii, 1844, 435, pi. 329. 

 Colymbus lumme, ButJNN., Oru. Bor. 1764, 39 (adult). 

 Cohjmbus stellaius, Bp.uxx., Orn. Bor. 1764, No. 130 (young).— Gm., Syst. Nat. i, 1788, 



687.— Lath., Ind. Orn. ii, 1790, 600.— Leach, Cat. 1816, 35. 

 Cnpphus stellatua, Pall., Zoog. R.-A. ii, 1811, — . 

 ColymluH lorcalis, BRtJxx., Orn. Bor. 1764, No. 131.— Lath., Ind. Orn. ii, 1790, 801.— 



Beehm, V. D. lt?A, 979. 

 Cohjmhus striatns, Gm., Syst. Nat. i, 1788, 586 (young).— Lath., Ind. Orn. ii, 1790, 802. 

 Coli/mhus riifogularis, Meyer, Tasch. Deutscb. Vog. ii, 453. 

 Colijnibm microrhynchua, Brehm., Naum. v, 1855, 300. 

 iZV(&.— The Northern hemisphere. 



Char. Bill usually slenderer than in the foregoing; culmen slightly concave at the 

 nostrils, gently convex to tip, Tvhich is rather obtuse and a little decurved. Outline of 

 rami nearly straight; gonys slightly convex. Front.il antia; scarcely extending beyond 

 base of nostrils. Tarsus relatively rather longer than in foregoing species, about four- 

 fifths the middle toe. 



Adult. — Bill black, rather lighter at the tip. Crown and broad cervical stripe glossy 

 greenish-black, the latter thickly streaked with white, which streaks, on the sides of 

 the breast, spread so as to nearly meet in front. Throat and sides of head clear bluish- 

 gray. A large, well-defined, triangular, chestnut-brown throat-patch. Entire upper 

 parts and sides under the wings deep brownish-black, with greenish gloss, everywhere 

 profusely spotted with white, the spots small, oval. Primaries blackish, paler on the - 

 inner webs. Tail n.arrowly tipped with ^Yhite. Under parts and lining of wings white, 

 the axillars with narrow, dusky shaft-streaks, and the lower belly, with some of the 

 under tail-coverts, du.sky. 



Yuung. — Bill mostly light bluish -white, with dusky ridge. Crown of head and neck 

 behind blaish-gray, the feathers of the former bordered with whitish. Entire upper 

 parts brownish- or grayish-black, everywhere' profusely marked with small oval and 

 linear spots of white. Throat without red patch, its sides and those of the the he.id 

 mottled with dnsky. Other parts as in the adult. 



Dimensions. — Length, about 27 ; wing, 11 or less ; bill along culmen, 2 ; along gape, 3 ; 

 heiglit at nostril, 0.50 ; width there, 0.35 ; tarsus, 2.75 ; outer toe, 3.50. 



Tliis species varies greatl,y in general size, and in the size and shape of the bill. 

 Nevertheless, it may always be recognized by the peculiar profuse spotting of the upper 

 Iiarts, as well as, when adult, by the red throat-patch. The spots are smallest and most 

 numerous on the wing-coverts aud upper back, where they grade into the streaks of 

 the bind neck ; largest on the tertials, scapulars, and sides under the wings, where they 

 are rather lines than spots, and are fewest, or almost wanting, on the middle of the 

 back. The marking results from a small spot or stripe ne.ir the end of each feather, 

 on the edge of each web ; there is occasionally a second pair nearer the base of the 

 feather. The amount of spotting is very variable with individuals ; in the young the 

 spots are always larger aud more numerous than in the adults, and usually lengthened 

 into oblique lines, producing a regular diamond-shaped reticulation. 



A specimen (No. 9923) collected by Mr. George Gibbs, on the Northwestern Bound, ry 

 Survey, is an albino — a state I have not observed in either of the other species. T.*;e 

 neck and upper parts are pure white, irregularly mottled with patches of light reddish- 

 nsb, of which color are the primaries, wing-coverta and flanks. The bill is slenderer 

 and more recurved than usual, the culmen being concave throughout. The specimen 

 measured 24 by 44 in extent, the wing 9.90. 



