Young. 
First year. 
Second 
year. 
Third 
year. 
410 
NATATORES. COLYMBUS. Diver. 
but becoming small and nearly round upon the lower 
part of the back and rump. Flanks and sides black, 
spotted with white. The rest of the under plumage 
white; the long axillary feathers the same, with a black 
stripe down their centres. ‘Tail short and rounded, 
black, consisting of twenty feathers. Legs greyish- 
black, paler on the inside. rides reddish-brown. 
The young of the year (Colymbus Immer, Auctor.) differ 
strongly from the adults, as follows :—Head, and back 
part of the neck, deep-grey, tinged with clove-brown. 
Fore part of the neck, and the under plumage, pure 
white, except the flanks, which are clove-brown. Up- 
per plumage deep clove-brown, the feathers being mar- 
gined with ash-grey. Upper mandible of the bill deep- 
grey, the under one much paler. 
After the second general moult, a darkish band appears 
on the middle of the neck, and the upper plumage be- 
comes darker, losing the pale grey edges that distinguish 
the young of the year, and a few white spots begin to 
shew themselves.—The succeeding moult developes still 
more the bar and neck collar; and the head and neck 
become darker, or of a blackish-green, speckled upon 
the chin and throat with white. The upper plumage 
also acquires its glossy black lustre, with the accompany- 
ing quadrangular white spots. In the next change, or 
when the bird has passed its third year, the plumage is 
perfected. 
