Black grouse

Lyrurus tetrix

Black grouse | APAM Archive

Species name: Lyrurus tetrix
Class: Birds
Order: Galliformes
Family: Tetraonidae
Common name: black grouse, blackcock


Distribution and habitat

The black grouse is present throughout northern Eurasia, from Great Britain to China and Siberia.
Spread throughout the Alps, it is present in both Marguareis and Alpi Marittime. It prefers sparse larch woodland or green alder where a variety of tall grasses, juniper bushes, bilberries, rhododendrons and rowan, provide the fruits and shoots it feeds on.


Appearance

The black grouse is between 40 and 55 cm long. Male and female are very different. Males have a shiny black plumage with blue highlights,a white vent and lyre-shaped tail. They weigh about 1.3 kg. have fleshy red eyebrows (caruncles), which are very visible in the mating season. Females are brown with lighter bands on their sides and they weigh under a kilo.
The species has particular adaptations to cold climates, such as nostrils covered with feathers, feathered tarsi and claws with horny rachis which spread the bird's weight out on the snow, these are present only in winter: it is a bit as if the black grouse has built-in snowshoes, which sprout only when needed! In Marguareis Park this bird, which has adapted to alpine climates, finds one of its most southern areas.


Feeding

The black grouse is herbivorous: leaves, buds, seeds, flowers and berries make up most of its diet. Chicks eat mainly insects, spiders, and other invertebrates.


Reproduction

In spring the black grouse lek, these are particularly spectacular shows. In high density sectors it is possible to observe dozens of males present on the same lek arena (normally a patch of residual snow) giving rise to clashes interspersed with emissions of croaking and characteristic puffs. The females, at the first light of dawn, reach the central parts of the arenas to mate with the dominant males who have conquered the most favourable positions. After a few days from mating, the females build a nest, on the ground, often hidden among the rhododendron or juniper bushes, in the woods or in the clearings, where 4 to 10 light yellow eggs with small brown spots are laid). The brooding lasts about 4 weeks in which the female only leaves the nest for food. The young stay with the hen until late autumn, and leave only after moulting to their adult plumage.


Did you know that ...?

Black grouse are characterized by cyclical fluctuations in population size, probably due to series of more or less favourable years. Climate is one of the factors that influence reproductive success: for example heavy rains in the period immediately following the hatching, late snowfall in June and low snowfall in winter have a very negative impact. It may seem strange that a small amount of snow is harmful to grouse, but for them, snow helps them to...protect themselves from the cold. Black grouse dig tunnels in the snow, often several metres long, where they spend the long winter nights, as shown by 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 outside there are peaks of over -20°C. Obviously, this favourable situation means that the grouse burn less calories, in the season when food has its minimum protein content: a good winter snow cover therefore ensures a higher survival rate for the species. In particular, the dense rhododendron bushes and the green alder thickets, which are expanding rapidly throughout the Alps, make the traditional hatching and rearing areas for their young less and less suitable.
Other negative elements for the survival of the species are to be found in the increase of the road network at high altitudes, with consequent human disturbance, in the construction of ski-lifts, in the irresponsible practice of off-piste skiing, in incorrect hunting, in the massive presence of wild boars destroying broods in the breeding areas in spring and in the first summer months.