The Black-Throated Diver — Colymbus Arcticus, Linnæus
The Black-throated Diver is very rare in England, and the few examples that are obtained are usually immature. In Ireland it has only been taken at long intervals, but in Scotland it breeds locally throughout the north and west.
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.