Species: Lyrurus tetrix
Common name: Black grouse, black cock
Habitat and distribution: The black grouse is present throughout northern Eurasia, from Britain to China and Siberia. Widespread throughout the Alps, it can be found in both Marguareis and Maritime Alps Parks . It prefers sparse woodland of larch or green alder in which it finds a variety of tall grasses, juniper bushes, bilberry bushes and thickets of rhododendrons and rowan trees on whose fruits and shoots it feeds.
Appearance: The Black Grouse is a bird measuring between 40 and 55 cm in length. The male and female are very different. The male has shiny black plumage with blue highlights and weighs about 1.3 kg. The white undertail and lyre-shaped rectrices distinguish its tail. It has fleshy red eyebrows (caruncules), which are highly visible in the mating season. The female is brown with lighter bands on her flanks and weighs less than one kilogram. The species has particular adaptations to cold climates, such as nostrils covered in feathers, feathered tarsi and fingers with horny rachis at the edges to increase the surface area for standing on the snow, which are only present in winter: it is a bit like black grouse having built-in snowshoes, which only appear when needed! The Marguareis Nature Park is one of the southernmost areas where this bird, which is adapted to alpine climates, can be found.
Feeding: The black grouse is a herbivore: leaves, buds, seeds, flowers and berries make up most of its diet. The chicks eat mainly insects, spiders, and other invertebrates.
Reproduction: In spring, the black grouse performs particularly spectacular leks. In areas of high density it is possible to observe dozens of males in the same arena or lek (normally a patch of residual snow), giving rise to clashes interspersed with characteristic croaking and hissing. The females, at first light, reach the central parts of the arenas to mate with the dominant males that have gained the most favourable positions. A few days after mating, the females build their nest, on the ground, often hidden among rhododendron or juniper bushes, in the woods or in clearings, where 4 to 10 eggs are laid (light yellow with small brown spots). The brooding lasts about four weeks and during this time the female only leaves the nest to feed. Until late autumn the young remain in the company of the hen and only leave once they have full adult plumage.
Did you know...: Black grouse are characterised by cyclical fluctuations in population size, probably due to a series of more or less favourable years. Climate is one of the factors influencing breeding success: for example, heavy rainfall in the period immediately after hatching, late snowfall in June and low snowfall in winter have a very negative impact. It may seem strange that a lack of snow would harm the Black Grouse, but for them snow is a way of... defending themselves against the cold. The black grouse digs tunnels in the snow, up to several metres long, in which it spends the long winter nights, as can be seen from the piles of droppings that emerge from the snow as it melts. Inside these tunnels, the temperature is around a few degrees below zero, even when the outside temperature is over 20 degrees below zero. Obviously, this favourable situation means that black grouse consume fewer calories in a season when food has the lowest protein content: good winter snow cover therefore ensures a higher survival rate for the species. The black grouse populations are also threatened by the progressive advancement of woodland to the detriment of pastures in the nesting areas: in particular, the very thick rhododendron formations and green alder stands, which are rapidly expanding throughout the Alps, make the traditional brooding and rearing areas less and less suitable for young birds.
Other negative elements for the survival of the species are to be found in the increase in roads and traffic at high altitudes, with consequent human disturbance, in the construction of ski-lifts, in the irresponsible off-piste skiing, in incorrect hunting, in the massive presence of wild boars that destroy the brood in the breeding areas in spring and early summer.