A large grouse native to Europe and N Asia, also known as capercailzie; usually solitary; forest-dwelling; males have special mating calls, and display by leaping into the air, flapping their wings. (Genus: Tetrao, 2 species. Family: Tetraonidae.)
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Least concern (LC) |
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Tetrao urogallus Linnaeus, 1758 |
The Capercaillie (also spelt Capercailzie), Wood Grouse or Western Capercaillie (Tetrao urogallus) is the largest member of the grouse family. The male is 74-90 cm in length, and the female 54-63 cm.
It is a sedentary species, breeding across northern parts of Europe and western and central Asia in mature conifer forests with diverse species composition and a relatively open canopy structure.
At one time it could be found in all the taiga forests of northern and northeastern Eurasia within the cold temperate latitudes and the coniferous forest belt in the mountain ranges of warm temperate Europe. In the Bavarian Forest, the Black Forest and the Harz mountains numbers of surviving Capercaillies decline even under massive efforts to breed them in captivity and release them into the wild.
The most serious threats to the species are habitat degradation, particularly conversion of diverse native forest into often single-species timber plantations, and to birds colliding with fences erected to keep deer out of young plantations.
Its name in English is derived from the Gaelic capull coille, meaning "horse of the woods".
Characteristics
Male and female Capercaillie - the cocks and the hens - can be discriminated easily by their size and colouration.
The hen is much smaller, weighing about half as much as the cock.
Both sexes have a white spot on the wing bow.
These so called "courting tacks" make a clear track in the snow in winter.
There is a bright red spot of naked skin above each eye.
There are several races, listed from west to east:
T. urogallus uralensis - Ural Mts., western SiberiaThe races show increasing amounts of white on the underparts of males from west to east, almost wholly black with only a few white spots underneath in western and central Europe to nearly pure white in Siberia, where the Black-billed Capercaillie occurs.
The small chicks resemble the hen in their cryptic colouration, which is a passive protection against predators.
The Capercaillie lives on a variety of food types, including buds, leaves, berries, insects, grasses and in the winter mostly conifer needles;
Capercaillies are not elegant fliers due to their body weight and short, rounded wings.
Behaviour and ecology
The Capercaillie is adapted to its original habitats - old coniferous forests with a rich interior structure and dense ground vegetation of Vaccinium species under a light canopy.
Capercaillie, especially the hens with young chicks, require a set of particular resources which should occur as parts of a small-scaled patchy mosaic: these are food plants, small insects for the chicks, cover in dense young trees or high ground vegetation, old trees with horizontal branches for sleeping.
In the lowlands such forest structures developed over centuries by heavy exploitation, especially by the use of litter and grazing livestock. In the highlands and along the ridges of mountain areas in temperate Europe as well as in the taiga region from Fennoscandia to Siberia the boreal forests show this open structure due to the harsh climate, hence offering optimal habitats for Capercaillie without human influence.
The Capercaillie is a highly specialized herbivore, which feeds almost exclusively on blueberry leaves and berries along with some grass seeds and fresh shoots of sedges in summertime.
During winter, when a high snow cover prevents access to ground vegetation, the Capercaillie spends almost day and night on trees, feeding now on coniferous needles of spruce, pine and fir as well as on buds from beech and rowan.
In order to digest this coarse winter food the birds need grit, small stones or gastroliths which they actively search for and devour.
The abundance of Capercaillie depends - like in most other species - on habitat quality, it is highest in sun-flooded open, old mixed forests with spruce, pine, fir and some beech with a rich ground cover of Vaccinium species.
Spring territories are about 250,000 square metres per bird.
Capercaillie are diurnal game, i.e.
The hens are ground breeders and spend the night on the nest. As long as the young chicks cannot fly the hen spends the night with them in dense cover on the ground.
Courting and reproduction
The courting season of the Capercaillie starts according to spring weather progress, vegetation development and altitude between March and April and lasts until May or June.
At the very beginning of dawn, the tree courting begins on a thick branch of a lookout tree.
It is only towards the end of the courting season that the hens arrive on the courting grounds, also called leks, meaning dance in Norwegian.
The cock flies from his courting tree to an open space nearby and continues his display.
There is a smaller courting peak in autumn, which serves to delineate the territories for the winter months and the next season.
About three days after copulation the hen starts laying eggs.
At the beginning of the breeding season the hens are very sensitive towards disturbances and leave the nest quickly.
After fledging the chicks are dependent on getting warmed by the hen.
They seek food independently and prey mainly on insects, like butterfly caterpillars and pupae (there is a specialised butterfly species whose caterpillars develop only on Vaccinium myrtillus), ants, myriapodae, ground beetles and the like.
They grow rapidly and most of the energy intake is transformed into the protein of the flight musculature (the white flesh around the breast in chickens).
From the beginning of September the families start to dissolve.
Conservation
The main causes for the recent decline of Capercaillie all over their range are climate change and nitrogen oxide emissions with their massive effects on vegetation development, intensified forestry and increasing disturbance by tourism and recreational use.
Conservation measures usually are confined to forestry and hunting practices.
It is imperative to conserve and create stable and mixed forests over large areas which fulfill all habitat requirements of Capercaillies. Especially the amount of old, open forests with rich ground vegetation dominated by Vaccicnium must be kept as high as possible, additionally habitat corridors and habitat stepping stones must be created between those old forest tracts which are used by Capercaillies.
Serious dangers come from deer fences which are responsible for 30% of all casualties in young Capercaillie.
Tourists can contribute to Capercaillie conservation by: staying on paths, especially during the breeding and fledging seasons from April through the end of July, also in winter, staying on paths in the game sanctuaries;
The late Alfred Brehm wrote in 1876 in his famous "Thierleben" (Animals' Life): "The largest and most distinguished of all grouse species is the Capercaillie, the grace of our forests, the joy of the gentle hunter".
It is only by joint and coordinated conservation efforts over large areas that we will be able to maintain this key species of mountain forests as part of our natural heritage.
In Scotland, the population has declined greatly since the 1960s because of deer fencing, predation and lack of suitable habitat (Caledonian Forest).
Hybrids
Capercaillie are known to hybridise occasionally with Black Grouse (these hybrids being known by the German name Rackelhahn), Common Pheasant and the closely related Black-billed Capercaillie.
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