General 
descrip- 
tion. 
Adult bird. 
416 NATATORES. COLYMBUS. Diver. 
of a plain oil-green, to which Tremminck, in his account, 
adds a few brown spots. It is, therefore, probable, that they 
are subject to some variation, from an immaculate to a spot- 
ted appearance. When fairly on wing, the Red-throated 
Diver flies with great strength and swiftness, and often at a 
considerable height ; but, except to descend from the lakes 
to the sea, or to perform its migrations, it seldom thus exerts 
its pinions, trusting, in avoidance of danger, more to its 
powers in diving ; and this it performs with as much ease as 
its congeners, remaining nearly as long submerged. Mon- 
racu, in the Supplement to his Ornithological Dictionary, 
under the article Speckled Diver (the young of this species), 
says that the distance between the place of immersion and 
emersion, in a bird which he pursued upon a canal, averaged 
from eighty to ninety yards; and that the rate of progress 
beneath the surface was between six and seven miles in the 
hour, whilst by swimming it did not exceed four and a-half. 
This species utters at times loud cries, and also hoarse croak- 
ings, which, having been observed by the natives to precede 
foul weather, have obtained for it the name of the Rain Goose 
in the Orkneys, where all the larger sea-fowl receive the ap- 
pellation of Goose, and the smaller ones that of Duck*. 
Piarte 78*. represents the Adult Bird, killed in the spring. 
Bill blackish-grey, two inches and two-eighths in length 
from the forehead to the tip; the upper mandible strait, 
the lower one with a long ascending angle, giving to the 
bill the appearance of being slightly recurved ; tomia 
of both mandibles much inflected and very sharp. Sides 
of the head, chin, and sides of the neck deep smoke- 
grey. Crown of the head blackish-grey ; the feathers 
being margined with smoke-grey. Nape and hind part 
of the neck glossy blackish-grey, margined with white. 
* Sir Witiram JarpDINE had a specimen of the Roller sent to him from 
Shetland, where it was killed, as a rare and curious Duck. 
5 
