COLYMBUS.] AVES NATATORES. 255 



The most abundant species in the genus. A frequent inhabitant of 

 ponds, marshes, lakes, and the hanks of rivers. Rarely observed on the 

 sea-coast. Feeds on Dyticidce and other aquatic insects. Is an excellent 

 diver. Constructs a large floating nest, which it attaches to the stems of 

 rushes. Eggs four to six in number. 



GEN. 101. COLYMBUS, Lath. 



269. C. glacialis, Linn. (Northern Diver.) Head 

 and neck violet-black, the latter with a double interrupted 

 white collar : bill upwards of four inches in length ; the 

 upper mandible nearly straight. 



C. glacialis, Temm. Man. d'Orn. torn. n. p. 910. Northern Diver, 

 Mont. Orn. Diet. Selb. IHust. vol. n. p. 406. pi. 76. Great 

 Northern Diver, Bew. Brit. Birds, vol. n. p. 174. 



DIMENS. Entire length thirty-three inches : length of the bill (from 

 the forehead) two inches eleven lines, (from the gape) four inches one 

 line ; of the tarsus three inches ; of the middle toe, nail included, four 

 inches two lines ; of the tail three inches six lines ; from the carpus to 

 the end of the wing thirteen inches six lines. 



DESCRIPT. (Adult.) Head and neck velvet black, with green and 

 purple reflections ; beneath the throat a transverse semilunar white band 

 with black streaks ; on the lower part of the neck an interrupted broad 

 collar, streaked longitudinally with black and white : all the upper parts 

 black, elegantly spotted with white; the spots on the back and rump 

 small and round ; those on the scapulars larger and of an oblong-square 

 form, disposed in rows, two at the extremity of each feather : quills and 

 tail without spots : breast and other under parts white ; flanks and sides 

 of the breast with a few black streaks : bill black ; the ridge of the upper 

 mandible very slightly arched above; lower mandible channelled beneath, 

 appearing deepest in the middle ; the gonys sloping upwards to the tip ; 

 tomia of both mandibles, but particularly of the lower one, inflected : 

 irides brown: feet externally dusky brown; the inner portions, and 

 membranes between the toes, whitish. (Young of the year.) Head, 

 occiput, and all the back part of the neck, cinereous brown; cheeks 

 speckled with white and ash-colour ; throat, front of the neck, and all 

 the other under parts, pure white; the feathers on the back, wings, 

 rump, and flanks, deep brown in the middle, the edges and tips ash- 

 colour : upper mandible cinereous gray ; lower mandible whitish. At the 

 age of one year, a transverse bar of dusky brown appears on the middle of 

 the neck, forming a sort of collar ; the back assumes a dusky tint, and 

 the small white spots begin for the first time to shew themselves. At the 

 end of the second year, the dusky bar on the neck extends further ; the 

 brown on the head and nape becomes mixed with greenish black ; the 

 spots on the back and wings increase in number, and the band on the 

 throat, and collar on the lower part of the neck, are more distinctly indi- 

 cated by longitudinal streaks of brown and white. At the age of three 

 years, the plumage is perfect. (Egg.) Dark olive-brown, with a few spots 

 of umber-brown : long. diam. three inches six lines ; trans, diam. two 

 inches three lines. 



A native of high northern latitudes. Abundant in the Orkneys, 

 Hebrides, and other Scotch islands, but very rare in the southern parts 



