The site chosen for the nest is usually an islet in some large loch, and the eggs, two in number, are olive brown, sparsely spotted with black and brown. The young when first hatched are of a uniform smoky grey-brown.
In its habits it closely resembles the next species. In summer the back is black, spotted with white, but the spots are not so uniformly distributed as in the former species. Crown and hind neck ash grey, chin and throat black, margined with short black and white stripes and a small band of similar stripes towards the upper end of the patch. Under parts white. The sexes are alike, but the females are slightly smaller. After the autumn moult the chin and throat are white and the upper parts ash brown.
The young bird resembles the young of the Great Northern Diver, but is much smaller and the neck is greyer. Length 27 in.; wing 11·75 in.
THE RED-THROATED DIVER
Colymbus septentrionalis, Linnæus
This species is the commonest of the Divers and may be found along all our coasts during the winter months. In the breeding season, except for a few pairs that may still be found on some of the Irish loughs, it is restricted to Scotland so far as our islands are concerned.
The eggs are laid close to the margin of some small tarn or on an islet in a large loch, but the former situation is the one preferred; they are elongate and olive brown, spotted with umber. The young leave the nest as soon as they are hatched, but they are not very strong divers at first and receive all their food from their parents; in fact this species often nests on ponds destitute of fish, and journeys several miles to the sea or large loch daily for its food. If the nest be approached the sitting bird glides off and dives without a ripple, reappearing again some way off. The note is a loud and mournful “kark, kark, kakera.”
In winter the adult is brown on the back, spotted with small white spots. The under parts are pure white, and head and neck, on which the feathers are very downy, are greyish brown on the crown and nape and white on the chin and throat. In summer the white spots on the back disappear; the crown and nape are slate grey streaked with black; the sides of the head and neck are pale grey and there is a longitudinal patch of chestnut down the fore-neck. The sexes are alike in plumage. The young bird in winter may be distinguished by the spots on the back being longer and tending to form arrow-shaped markings, and the feathers of the vent have narrow brown margins. Length 24 in.; wing 11·2 in.
RED-THROATED DIVER
Colymbus septentrionalis
Adult in summer (right). Young (left)