Western capercaillie

The western capercaillie is the largest member of the grouse family, a family of game birds. It is a shy bird and has been called the "Eurasian capercaillie," "cock of the wood," and "wood grouse." The bird's name comes from the words capull coille in the Gaelic language, which means "horse of the wood."

Kingdom: Animalia

Phylum: Chordata

Class: Aves

Order: Galliformes

Family: Tetraonidae

Genus: Tetrao

Species: Urogallus

Capercaillies inhabit the forested mountains of northern Europe and western to central Asia. They hide amid the dense pine trees and surrounding ground cover. During the summer, these herbivores forage for berries, blueberry leaves, and shoots of sedges (coarse grasses). Throughout autumn, the birds take advantage of grain available in nearby fields. In the winter, they eat pine and spruce needles and beach and rowan tree buds. Capercaillies have powerful, hooked bills for clipping and snipping their food from trees and bushes.

Capercaillies are 21 to 33 1/2 inches (54 to 85 centimeters) long and have wingspans of 27 1/2 to 49 inches (70 to 125 centimeters). The round, plump bodies of females have plumage, or feathering, of brown, white, and black. Their upperparts are a mixture of these three colors but are mainly brown. Their undersides are mainly white with black and brown. They weigh 3 1/3 to 11 pounds (1 1/2 to 5 kilograms). Males are more colorful with blue-black plumage on their upperparts, glossy-green breasts, and chestnut wings with white patches. Their bellies and erect, fanned, tails also have small white spots. A bright red patch above each eye looks like a large eyebrow and inflates during mating.

Male capercaillies live alone most of the year but are social birds in the fall after the breeding season. They usually keep out of sight under the cover of vegetation where they build their nests during the spring and summer. In the winter, they begin perching and roosting in trees. Capercaillies do not need to migrate for winter because they store layers of fat in their bodies to keep them warm.

From April to July, male capercaillies gather in small groups in areas called leks or lekking grounds. In these areas, they fight displaying their bright plumage by fanning their tail feathers. They have been known to attack anything that moves, even sheep, people, and cars. As they strut across the ground, the males ruffle their throat feathers and make loud, harsh clicking, popping, gurgling, and grating noises. They may call so loudly, intently, and for such long periods that the blood rushing through their heads blocks their ear passages and the nerves of their eyes causing temporary deafness and blindness. The females watch this activity and wait for the winners to lead them away to mate. A dominant male may beat other males several times and have more than one female mate. These females form his harem for that year's mating season, but he usually leaves them after mating.

After mating, the females dig out small, shallow holes in the ground and make soft beds inside them with pine needles, moss, grass, and heather. Nests rest near the bases of trees and in the undergrowth. She incubates 8 to 12 eggs for 26 to 28 days before the young hatch from their speckled shells. The eggs' colors and the female's plumage help camouflage them from predators. The chicks can leave the nest a few hours after hatching and three to four weeks later, the chicks can fly. With their mothers, the young eat buds, berries, and shoots. They also learn to catch grasshoppers, spiders, bugs, ants, beetles, moths, and insect larvae. After six weeks when the young no longer depend on the mother for warmth, the group begins to dissolve. They may form new foraging groups during the winter.

Capercaillies have life spans of up to 10 years.

Bibliography

Hill, Laurel. "Tetrao Urogallus." Animal Diversity Web, animaldiversity.org/accounts/Tetrao‗urogallus. Accessed 25 Mar. 2024.