510 COLYMBIDAs 
and white; breast and abdomen, white; long under tail- 
coverts, sides, and flanks, mostly black. 
Adult female nuptial.—Similar in plumage to the male. 
Adult winter, male and female.—Chin, throat, fore-neck, 
breast, and abdomen, white; back, scapulars, and wings, 
chiefly deep ashy-brown; top of head and back of neck, 
light brown, becoming darker on the sides of the neck ; 
sides and flanks, brownish-black. 
Immature, male and female. — Resembles the adult 
winter-plumage except that the feathers of the back, the 
scapulars, wing-coverts, rump, and upper tail-coverts, are 
brownish, broadly margined with grey. 
Beak. Bluish-black. 
Fret. Brownish-green. 
IRIDES. Red. 
AVERAGE MEASUREMENTS. 
TOTAL LENGTH ... ... 275 in, Female smaller: 
WING See mh etd 2 dalton 
3BAK oS a. ons, BRIA Se, 
TARSO-METATARSUS Ree Ro ee 
EGG ae nd A cee) FOR Seen oeiitie 
Allied Species and Representative Forms.—C. pacificus, 
paler on the nape and on the back of the neck, inhabits the 
north-western parts of North America, migrating south to 
California in winter, and it has been recorded from Japan 
(W. R. Ogilvie-Grant, Cat. Birds Brit. Mus., vol. xxvi, pp. 
495-96). 
RED-THROATED DIVER. Colymbus septentrionalis (Linneus). 
Coloured Figures.—Gould, ‘ Birds of Great Britain,’ vol. v, pl. 
45; Dresser, ‘ Birds of Europe,’ vol. viii, pl. 628; Lilford, 
‘Coloured Figures,’ vol. vi, pl. 47. 
The Red-throated Diver is common and widely-distri- 
buted in autumn and winter on British waters. It appears, 
as a rule, in the latter end of October, though I have seen 
