Genus COLYMBUS, Lath. 
Gen. Cuar. Bill longer than the head, strong, straight, compressed, and sharp-pointed. 
Nostrils basal, lateral, linear, oblong, pervious, half closed by a membrane. Wings 
short, acuminate, having the first quill-feather the longest. Taz/ short and rounded. 
Tars: thin, very much compressed. Feet large, of four toes, three before and one behind; 
outer toe exceeding the middle one in length; front toes entirely webbed; hind toe 
furnished with a lobe, and partly connected with the exterior membrane of the inner toe. 
Nails flat and broad. 
NORTHERN DIVER. 
Colymbus glacialis, Lenn. 
Le Plongeon Imbrin. 
Tus noble species of Diver, the largest and most typical of its genus, appears to be equally dispersed over 
the whole of the northern hemisphere, giving preference to the regions within the arctic circle during sum- 
mer, and progressing southward as far as latitude 36° on the approach of autumn and winter, at which 
seasons they are by no means of rare occurrence in our own islands, although, in accordance with that general 
law of Nature which causes the young to wander furthest from their native habitat, we find a much greater pro- 
portion of immature birds than of those which bear the beautifully contrasted livery of the adult. The great 
dissimilarity of plumage which characterizes the species at different ages has caused much confusion in its 
nomenclature, the bird of the first year having been described as specifically distinct from the adult, while, 
again, those of the second year, when they have partially assumed the mature livery, have been considered as 
differing from both. In this latter state they are frequently met with round our coasts, but less so than the 
birds of the first year, which may be very commonly observed even in our lakes and estuaries. 
M. Temminck states that on the European Continent it gives a preference to the shores of the sea, although 
the young are frequently found up the large rivers ; and even the German and Swiss lakes are not altogether 
exempt from its visits. ‘That it inhabits the shores of the Black Sea, and without doubt the Mediterranean, is 
a fact with which we are made acquainted by the circumstance of the Zoological Society’s having received an 
individual, in the second year’s plumage, from their valued correspondent Keith E. Abbot, Esq., of Trebizond. 
We have before alluded to the far-extended wanderings of the young migratory birds ; and as no instance is 
on record of these birds having bred in southern latitudes, we may reasonably infer that the individual above 
mentioned had wandered from the regions of the arctic circle, which form their almost exclusive summer 
residence and breeding-place. Are we, then, to presume that the individuals found in the Black Sea have 
proceeded thither by way of the Atlantic Ocean and Mediterranean Sea, or by crossing partially over land, 
following the course of the large rivers, as the Danube, the Don, the Volga, &c.? We incline to the latter 
supposition, as all migratory animals pursue, with as little deviation as possible, a course from north to south, 
or vice versa. 
Its dependence for food rests entirely on its great activity in diving, as it subsists solely, whether at sea or 
in fresh water, upon fish, aquatic insects, &c., in the capture of which it displays astonishing agility and 
rapidity of motion. 
The situation chosen for the purpose of nidification are the borders and islands of inland seas, lakes, and 
rivers ; the nest being placed close to the water’s edge, so as to be easily accessible to the parent, whose 
perfect adaptation for progression on the water, its natural element, totally unfits it for walking, though it 
contrives to propel itself forward by means of resting’ its breast upon the ground and striking backward with 
its feet, somewhat like the action of swimming. 
The plumage of the sexes is strictly similar, the adults having the top of the head and neck fine black 
glossed with purplish green; a transverse bar of white spotted with black crosses the throat, and a wider 
band of the same colour passes lower down upon the back part of the neck; the whole of the upper surface 
glossy black, each feather having white spots, one on each side the shaft, forming rows, those on the scapu- 
laries becoming larger and square, but continuing small and nearly round on the back and rump ; primaries 
black without spots; flanks and sides black spotted with white; whole of the breast and under surface white ; 
bill and legs black ; irides reddish brown. 
The young of the year has the top of the head, back of the neck, upper surface, and flanks light greyish 
brown, the centre of each feather being darker; under surface pure white; bill, inner side of the tarsi, and 
interdigital membrane fleshy greyish white ; outer side of the tarsi and toes brownish black. 
The Plate represents an adult male and a young bird of the year, about two thirds of the natural size. 
