Western Capercaillie

The Western Capercaillie is an enormous grouse, the largest in the world, with males dwarfing females dramatically. Males are turkey-sized, with glossy blackish plumage tinged with dark green on the breast, a fan-shaped tail often raised and spread in display, and a heavy pale bill. Females are far smaller, mottled brown, buff, and chestnut, with a rounded rusty-orange breast patch, providing effective camouflage on the forest floor.

It is a bird of old, structurally rich coniferous forest, and is best known for its dramatic and unusual dawn courtship display, in which males produce a bizarre sequence of clicking, gurgling, and popping sounds unlike almost any other bird.

Key field marks

• Male: huge size, blackish body with green-glossed breast, fan-shaped tail, pale bill
• Female: much smaller, mottled brown and chestnut with a rusty breast patch
• Loud wing-clapping in flight due to sheer size and weight
• Bizarre, mechanical-sounding courtship song: clicks building to a pop and a grinding finish

Similar species

• Black Grouse male is smaller with a lyre-shaped tail and lacks the Capercaillie's fan tail and bulk.
• Female Capercaillie can resemble female Black Grouse but is notably larger, with a more contrasting rusty breast patch.

Sheer size distinguishes the Western Capercaillie from all other European grouse.

Habitat

Requires extensive, mature coniferous forest, particularly Scots pine, with an open canopy structure and a rich understory of bilberry and other berry-bearing shrubs.

Range

Found patchily across Scandinavia, the Alps, Pyrenees, Carpathians, and the boreal forest belt of Russia; a relict, vulnerable population survives in the Scottish Highlands.

Migration

Resident and sedentary, with limited dispersal from natal forest.

Behavior

Males gather at traditional lek sites in the pre-dawn darkness in spring, performing an elaborate display combining fanned tails, raised head plumes, and a remarkable vocal sequence to attract and compete for females, often becoming highly aggressive toward rivals and even, occasionally, toward humans.

Voice

The male's display song is a strange, mechanical series of double-clicks accelerating into a "pop" like a cork, followed by a wheezing, grinding sound, quite unlike typical bird song.

Feeding

Feeds heavily on pine needles and shoots, especially in winter, along with berries such as bilberry and seeds; chicks depend more on insects in early weeks.

Nesting and breeding

Females nest alone on the ground, often at the base of a tree, laying 5-8 eggs incubated for about 24-26 days, and raise the brood without help from the male.