The booming sound made by a male capercaillie, a bird that weighs as much as five kilos, taking flight in a forest will make the casual observer at least jump. The quite considerable amount of noise would easily make you think that a much larger beast is moving about. A capercaillie hen is substantially smaller than the cock, and the colouring of males and females also differs a great deal. The cock’s plumage is a festive brown-black and its tail large and handsome, while the hen’s feathers are a more modest variegated brown.
The capercaillie thrives in coniferous forests and pine bogs
The capercaillie is often considered an old-growth forest species, but this is not necessarily so. A typical habitat for these birds is a varied coniferous or mixed forest dotted with openings and bogs. The capercaillie prefers different habitats in different seasons. They winter in pine-dominated forests and often prefer tree-covered boglands. At this time of year, their diet consists of only pine needles. De-needled pine trees that have been used as a source of nourishment by the capercaillie can often be spotted along the edges of pine bogs. In summer, these birds favour, among others, the wet spruce forests and lush stream sides that contain lots of eatable insects, buds, shoots and berries.
The capercaillie hen is not fussy about choosing a nesting site. Its nest is a humble hole in the ground that is lined with some twigs and may be found on the edge of an opening or deeper inside the forest – any spot, which provides cover from predators, will do.
Groups of capercaillie perform impressive courting displays in spring. This usually takes place in mature, but open coniferous forests. The cocks gather in the same courting or lekking ground each year. This venue is also where the pairs mate. The strongest alpha-cock will mate with the largest number of hens. Each cock has his own lekking territory around the lekking ground. In addition to this two- to three-hectare lekking territory, each cock that participates in the lek has a more extensive daytime territory. The entire lekking site with its lekking and daytime territories can cover tens or even hundreds of hectares of varied woodlands depending on the number of participating cocks.
Trees left unfelled to safeguard lekking territories
Present-day forestry practices takes account of the capercaillie’s lekking behavior. The central lekking ground is often left completely untouched and the forest cover of the surrounding lekking territories is also looked after. Felling is performed in phases and logging sites are small enough to not disturb capercaillie daytime habitats.. Leaving stretches of tree cover to connect daytime territories to the lekking ground is also an important consideration.
Capercaillie occurs extensively in Europe’s coniferous forests
Capercaillies are found throughout Finland excluding the Åland Islands, the outer archipelago and the treeless fells of Lapland. The capercaillie is distributed from the coniferous zone of Europe to the central Siberian taiga, in addition to which a separate population is found in Scotland.
Population sizes vary a great deal
It is natural for the populations of all grouse to vary strongly because of reasons that are not always understood. Forestry activities, hunting, the abundances of different small predators and the occurrence of disease affect capercaillie population numbers. Even weather, such as rainy and cold or especially dry and hot summers, has its impact on the number of chicks produced by various grouse species.
The capercaillie population of Finland has been decreasing since the 1960s and it is estimated to now stand between 50,000 and 150,000, or even 250,000, pairs. According to the International Union for Conservation of Nature, Europe’s nesting population ranges from 760,000 to 1,000,000 pairs. The capercaillie is a threatened species in many European countries, but it is classified as near-threatened in Finland. Hunters hold the capercaillie in high regard and cooperate with scientists to safeguard the population. Many hunting clubs have voluntarily protected the species in Southern Finland especially.
The UN has named 2010 the International Year of Biodiversity. For the rest of the year, this series of articles will focus on concepts and phenomena related to the diversity of nature.