CAPERCAILLIE (CAPERCAILZIE or CAPERCALLY), a bird's name derived from the Gaelic. The bird (Tetrao urogallus) be came extinct in the British Isles about 175o, but was re-intro duced in Scotland at the beginning of the 19th century and is now tolerably abundant. This species is. widely, though intermittently, distributed on the Continent of Europe, from Lapland to the northern parts of Spain, Italy and Greece, but is always restricted to pine forests, which alone afford it food in winter. Its bones have been found in the kitchen middens of Denmark and the caves of Aquitaine. It inhabits the forests of a great part of Siberia. On the Stannovoi mountains, however, it is replaced by a nearly allied species (T. urogalloides), which is smaller with a slenderer bill, but longer tail.
The male, known as the mountain cock or cock of the woods, is remarkable for his large size and dark plumage, with the breast metallic green. He is polygamous, and in spring mounts to the topmost bough of a tall tree, whence he challenges all comers by extraordinary sounds and gestures ; while the hens, which are much smaller and mottled in colour, abide below the result of the duels. The hen nests on the ground, and lays from seven to nine or even more eggs. The young are able to fly soon after they are hatched, and towards the end of summer, from feeding on the fruit and leaves of the bilberries and other plants, get into excellent condition and become good eating. With the first heavy falls of snow they. betake themselves to the trees, and then, feeding on the pine-leaves, their flesh speedily acquires a distasteful flavour of turpentine. Hybrids are frequently pro duced between the capercaillie and the black grouse (T. tetrix).