alcidje—phaleridin.E: auklets, etc. 



1079 



Fig. 738. — Pigeon Guillemot, nat. size. 



rump aud under parts, white; back and mure or less of hind neck and head bhick, variegated 

 with wliite. Young in first plumage : Bill black; feet dusky reddish. Upper parts plumbeous 

 or sooty, little varied with white; under parts white, marbled, rayed, and waved with dusky; 

 incipient mirror spotty. Nestlings are covered with 

 sooty brownish-black down ; bill and feet brown- 

 ish-black. Perfectly white {lacteolus, niveus) and 

 entirely black {motzfeldi, unicolor) birds are rarely \^J 

 seen. In some cases, very old birds remain black 

 in winter. The mirror on the upper surface of 

 the wings is composed of the terminal half (more 

 or less) of the greater coverts, the rest dark ; of 

 the several next rows excepting their dark bases, 

 the white of these coverts noruially overlying and 

 concealing the dark basal portions of the greater 

 coverts, so that the oval mirror is usually unbroken ; the anterior border of the mirror is the 

 line through the union of white tips with dark bases of the row of lesser coverts about 5- an 

 inch from the fore-arm edge of the wing. When, as not seldom happens, the row of gi-eatest 

 coverts are dark beyond the extent of the next row, this dark uncovered portion shows as a 

 wedge partly splitting the mirror, as normally occurs in U. columba. Or, the greater row of 

 coverts may be entirely dark, when the mirror is unbroken, as before, but much smaller; or, 

 again, the middle row of coverts may be tipped with dark, making a break across the mirror, 

 but in a different method from that first described. Finally, the mirror may be only indicated 

 by isolated white feathers, or wholly wanting. Length, average, 13.00 ; extent, average, 

 22.50; wing G.00-6.25; tail about 2.00; tarsus 1.25; middle toe and claw 1.75; bill 1.30; 

 gape 1.75; gonys 0.65; depth of bill at base 0.45, width 0.35. Europe and North Ameri- 

 can coasts and islands of the Nortli At- 

 lantic, very abundant; not authentic in 

 the North Pacific, where replaced by 

 columba ; not occurring in the Arctic 

 Ocean, where replaced by mandti ; in 

 North America breeding in southern 

 Greenland, Labrador, Magdalen islands, 

 and Newfoundland, and S. to islands 

 of Maine coast; S. in winter to the 

 Middle States. Gregarious; flying in 

 close flocks low over the water ; nesting 

 scattering in rifts of rock near the water; eggs 2-3, sea-green, greenish-white or white, spotted 

 and blotched most irregularly with blackish-brown, and with purplish shell-markings; size 

 2.25-2.50 X 1.50-1.60; shape nearly elliptical, not pyriform like those of Guillemots; laid in 

 June, July. Uria gnjlle, in part, of former editions of the Key, including C. maniJii. Cephus 

 gnjlle Hukiim. 1831. Ccpphua grylle Naum. 1844; A. 0. U. Lists, 1886-95, No. 27. Uria 

 unicolor Fabku, and U. motzfcldi Benicken, 1824, are believed to be a melanism of grylle: 

 but Cepphus motzfeldi Stej. Pr. U. S. Nat. Mus. vil, Aug. 5, 1884, p. 210; B. B. &. 11. 

 Water B. N. A. ii, Sept. 1884, p. 497 ; A. 0. U. Hypothetical List, 1886-95, No. 2. is com- 

 pared with C. cnrbo. 



C. coliini'ba. (Lat. co/«Hi&rt, a pigeon. Fig. 738.) Pic.EOx GuiLi.i;M(iT. Bill stouter than 

 that of r/z-y/Zr, and more obtuse. No wliitc on under surface of wing. Wiiite mirror of upper 

 surface nearly split in two by an oblique dark line, caused by extension of dark bases of greater 

 coverts in increasing amount from within outward, till the outermost are scarcely tipped with 

 white ; consequently there is a darii wrdge between tlic wliite ends of greater and middle rows 



Fia. 739. — Sooty Guillemot, nat. size. 



