Western capercaillie
Western capercaillie | |
---|---|
Male (cock) | |
Female (hen) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Galliformes |
Family: | Phasianidae |
Genus: | Tetrao |
Species: | T. urogallus
|
Binomial name | |
Tetrao urogallus | |
Range of the western capercaillie[2] | |
Distribution in Europe[2] |
The western capercaillie (Tetrao urogallus), also known as the Eurasian capercaillie, wood grouse, heather cock, cock-of-the-woods, or simply capercaillie
The western capercaillie is one of two living species under the genus Tetrao, which also includes the lesser-known black-billed capercaillie.
Etymology
The word capercaillie is a corruption of the
The genus name is derived from the Latin name of a game bird, probably the black grouse. The species name, urogallus, is a Neo-Latin partial homophone of German Auerhuhn.[5]
Taxonomy
The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae under its current binomial name.[6]
Its closest relative is the black-billed capercaillie, Tetrao parvirostris, which breeds in the larch taiga forests of eastern Russia and parts of northern Mongolia and China.
Subspecies
The western capercaillie has 8 recognized subspecies:[7]
- T. u. cantabricus (Castroviejo, 1967) - northwestern Spain
- T. u. aquitanicus (Ingram, 1915) - Pyrenees of Spain and France
- T. u. crassirostris (C.L. Brehm, 1831) - Alps to Estonia
- T. u. rudolfi (Dombrowski, 1912) - Bulgaria to southwestern Ukraine
- T. u. urogallus (Linnaeus, 1758) - Scandinavia and Scotland
- T. u. karelicus (Lönnberg, 1924) - Finland and Karelia
- T. u. lonnbergi (Snigirevski, 1957) - Kola Peninsula
- T. u. pleskei (Stegmann, 1926) - Belarus (Russia)
- T. u. obsoletus (Snigerewski, 1937) - northern European Russia
- T. u. volgensis (Buturlin, 1907) - found in southeastern European Russia
- T. u. uralensis (Nazarov, 1886) - found in the Urals and western Siberia
- T. u. taczanowskii (Stejneger, 1885) - central Siberia to Altai Mountains (northwest Mongolia and eastern Kazakhstan)
Subspecies of the western capercaillie show increasing amounts of white on the underparts of males distributed 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 is located. There is less variation in the females of this species.
A native Scottish population of western capercaillie which became extinct between 1770 and 1785 was probably a distinct subspecies, although it was never formally described as such. The western capercaillie found in
Hybrids
Western capercaillies are known to hybridise occasionally with black grouse (these hybrids being known by the German name Rackelhahn) and the closely related black-billed capercaillie.
Description
Male and female western capercaillie can easily be differentiated by their size and colouration. The cock is much bigger than the hen. It is one of the most sexually dimorphic in size of living bird species, only exceeded by the larger types of bustards and a select few members of the pheasant family.
Cocks (males) typically range from 74 to 85 centimetres (29 to 33 inches) in length with wingspan of 90 to 125 cm (35 to 49 in) and an average weight of 4.1 kg (9 lb 1 oz).[9][10][11] The largest wild cocks can attain a length of 100 cm (40 in) and weight of 6.7 kg (14 lb 12 oz).[12] The largest specimen recorded in captivity had a weight of 7.2 kg (15 lb 14 oz). The weight of 75 wild cocks was found to range from 3.6 to 5.05 kg (7 lb 15 oz to 11 lb 2 oz).[11] The body feathers are dark grey to dark brown, while the breast feathers are dark metallic green. The belly and undertail coverts vary from black to white depending on race (see below).
The hen (female) is much smaller, weighing about half as much as the cock. The capercaillie hen's body from beak to tail is approximately 54–64 cm (21–25 in) long, the wingspan is 70 cm (28 in) and weighs 1.5–2.5 kg (3 lb 5 oz – 5 lb 8 oz), with an average of 1.8 kg (3 lb 15 oz).[11] Feathers on the upper parts are brown with black and silver barring; on the underside they are more light and buffish yellow.
Both sexes have a white spot on the wing bow. They have feathered legs, especially in the cold season, for protection against cold. Their toe rows of small, elongated horn tacks provide a snowshoe effect that led to the German family name "Rauhfußhühner", literally translated as "rough feet chickens".
These so-called "courting tacks" make a clear track in the snow. The sexes can be distinguished very easily by the size of their footprints.
There is a bright red spot of naked skin above each eye. In German hunters' language, these are the so-called "roses".
The small chicks resemble the hen in their cryptic colouration, which is a passive protection against predators. Additionally, they wear black crown feathers. At an age of about three months, in late summer, they moult gradually towards the adult plumage of cocks and hens. The
Distribution and habitat
The capercaillie is a non-migratory
At one time it was present in all the
The most serious threats to the species are
Status and conservation
This species has an estimated range of 1,000,000–10,000,000 km2 (390,000–3,860,000 sq mi) and a population of between 1.5 and 2 million individuals in Europe alone. There is some evidence of a population decline,
As reported by the Spanish researcher
In
A study published in 2022 by NatureScot scientific advisory committee[16] recommended 'renewed intensive measures' to maintain the population, especially steps to assist in the survival of eggs and chicks. Predators like crows, foxes and pine martens are blamed for the decline, as well as the deer fences, and increased human recreation in the territory which can injure adult birds.It was declared as 'extremely vulnerable' and requiring urgent action. Biodiversity Minister for Scotland, Lorna Slater, MSP described capercaillie as 'magnificent birds' and ' iconic' for Scotland and called for 'partnership working' to reverse the decline.[17]
Behaviour and ecology
The western 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. They mainly feed on Vaccinium species, especially bilberry, find cover in young tree growth, and use the open spaces when flying. As habitat specialists, they hardly use any other forest types.
Western capercaillies are not elegant fliers due to their body weight and short, rounded wings. While taking off they produce a sudden thundering noise that deters predators. Because of their body size and wingspan they avoid young and dense forests when flying. While flying they rest in short gliding phases. Their feathers produce a whistling sound.
Western capercaillie, especially the hens with young chicks, require resources that 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. These criteria are met best in old forest stands with spruce and pine, dense ground vegetation and local tree regrowth on dry slopes in southern to western expositions. These open stands allow flights downslope, and the tree regrowth offers cover.
In the lowlands such forest structures developed over centuries by heavy exploitation, especially by the use of litter and grazing
The abundance of western capercaillie depends—as with most 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 25 hectares (62 acres) per bird. Comparable abundances are found in taiga forests. Thus, the western capercaillie never had particularly high densities, despite the legends that hunters may speculate about. Adult cocks are strongly territorial and occupy a range of 50 to 60 hectares (120 to 150 acres) optimal habitat. Hen territories are about 40 hectares (100 acres). The annual range can be several square kilometres (hundreds of hectares) when storms and heavy snowfall force the birds to winter at lower altitudes. Territories of cocks and hens may overlap.
Western capercaillie are diurnal game, i.e., their activity is limited to the daylight hours. They spend the night in old trees with horizontal branches. These sleeping trees are used for several nights; they can be mapped easily as the ground under them is covered by pellets.
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. During winter the hens rarely go down to the ground and most tracks in the snow are from cocks.
Diet
The western capercaillie lives on a variety of food types, including buds, leaves,
The western capercaillie is a highly specialized herbivore, which feeds almost exclusively on blueberry leaves and berries with some grass seeds and fresh shoots of sedges in summertime. The young chicks are dependent on protein-rich food in their first weeks and thus mainly prey on insects. Available insect supply is strongly influenced by weather—dry and warm conditions allow a fast growth of the chicks, cold and rainy weather leads to high mortality.
During winter, when a high snow cover prevents access to ground vegetation, the western capercaillie spends almost all day and night in trees, feeding on coniferous needles of spruce, pine and fir as well as on buds from beech and rowan.
To digest this coarse winter food, the birds need grit: small stones or
A recent study using DNA from faeces in Norway and France found that their diet is much more varied than had been documented.[18]
Courting and reproduction
The breeding season of the western capercaillie starts according to spring weather progress, vegetation development and altitude between March and April and lasts until May or June. Three-quarters of this long courting season is mere territorial competition between neighbouring cocks or cocks on the same courting ground.
At the very beginning of dawn, the tree courting begins on a thick branch of a lookout tree. The cock postures himself with raised and fanned tail feathers, erect neck, beak pointed skywards, wings held out and drooped and starts his typical aria to impress the females. The typical song in this display is a series of double-clicks like a dropping ping-pong ball, which gradually accelerate into a popping sound like a cork coming off a champagne bottle, which is followed by scraping sounds.
Towards the end of the courting season the hens arrive on the courting grounds, also called "lek", Swedish for "play". The cocks continue courting on the ground: This is the main courting season. The cock flies from his courting tree to an open space nearby and continues his display. The hens, ready to get mounted, crouch and utter a begging sound. If there is more than one cock on the lek, it is mainly the alpha-cock who engages in copulation with the hens. In this phase western capercaillies are most sensitive to disturbances. Even single human observers may cause the hens to fly off and prevent copulation in this very short time span where they are ready for conception.
In Nordic countries male western capercaillies are reputed for their combative behavior during mating season, sometimes chasing off any people who enter their territory.[19][20][21] In a study it was found that the testosterone level in such "deviant" males was about five times higher than that of normal displaying males.[22]
There is a smaller courting peak in autumn, which serves to delineate the territories for the winter months and the next season.
Egg-laying
About three days after copulation the hen starts laying eggs. In 10 days the clutch is full. The average clutch size is eight eggs but may amount up to 12, rarely only four or five eggs. Brooding lasts about 26–28 days according to weather and altitude.
At the beginning of the brooding season, the hens are very sensitive to disturbances and leave the nest quickly. Towards the end they tolerate disturbances to a certain degree, crouching on their nest which is usually hidden under low branches of a young tree or a broken tree crown. As hatching nears, hens sit tighter on the nest and will only flush from the nest if disturbed in very close proximity. Nesting hens rarely spend more than an hour a day off of the nest feeding and as such become somewhat constipated. The presence of a nest nearby is often indicated by distinctively enlarged and malformed droppings known as "clocker droppings". All eggs hatch in close proximity after which the hen and clutch abandon the nest where they are at their most vulnerable. Abandoned nests often contain "caeacal" droppings; the discharge from the hens' appendixes built up over the incubation period.
Hatching and growth
After hatching the chicks are dependent on getting warmed by the hen. Like all
They seek food independently and prey mainly on insects, like butterfly caterpillars and pupae, ants, myriapodae, ground beetles.
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). At an age of 3–4 weeks they are able to perform their first short flights. From this time on they start to sleep in trees on warm nights. At an age of about 6 weeks they are fully able to maintain their body temperature. The down feathers have been moulted into the immature plumage and at an age of 3 months another moult brings in their subadult plumage; now the two sexes can be easily distinguished.
From the beginning of September the families start to dissolve. First the young cocks disperse, then the young hens. Both sexes may form loose foraging groups over the winter.
Predation and hunting
Mammalian predators known to take capercaillie include
A traditional gamebird, the capercaillie has been widely hunted with guns and dogs throughout its territory in central and northern Europe. This includes trophy hunting and hunting for food. Since hunting has been restricted in many countries, trophy-hunting has become a tourist resource, particularly in central European countries. In some areas, declines are due to excessive hunting, though this has not generally been a global problem. The bird has not been hunted in Scotland or Germany for over 30 years.[32]
References
- ^ . Retrieved 18 November 2021.
- ^ a b BirdLife International and NatureServe (2014) Bird Species Distribution Maps of the World. 2012. Tetrao urogallus. In: IUCN 2014. The IUCN Red List of Threatened Species. Version 2014.3. http://www.iucnredlist.org. Downloaded on 02 June 2015.
- ^ ISBN 9780521152532
- ISBN 978-0198661962.
- ISBN 978-1-4081-2501-4.
- ^ Linnaeus, Carl (1758). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata (in Latin). Holmiae (Stockholm): Laurentii Salvii. p. 159.
F. cera pedibusque flavis, dorso fusco, nucha alba abdomine pallido maculis oblongis fuseis.
- .
- .
- ^ "Capercaillie (Tetrao urogallus)". ARKive. Archived from the original on 2012-08-23. Retrieved 2012-12-26.
- ^ "Western capercaillie". World Association of Zoos and Aquariums (WAZA). Archived from the original on 2011-01-07. Retrieved 2012-06-21.
- ^ ISBN 978-0-8493-4258-5.
- ^ "Capercaillie". BBC Nature – Wildlife. Archived from the original on 2017-10-21. Retrieved 2012-06-21.
- ^ a b Maakuntatunnukset – Keski-Suomen Liitto (in Finnish)
- ISBN 951-593-915-1
- S2CID 216382815.
- ^ "Review of Capercaillie Conservation and Management - Report to the Scientific Advisory Committee". NatureScot. Retrieved 2022-02-26.
- ^ Young, Gregor (26 February 2022). "New extinction fears for the capercaillie". The National. p. 21.
- S2CID 238773874.
- ^ "Sex-crazed grouse terrorizes Swedish family". The Local. 3 May 2015. Retrieved 8 May 2020.
- ^ Suter, Paul (12 November 2019). "Capercaillie in Finland". Too Much To See. Retrieved 8 May 2020.
- ^ "Capercaillie". Harjureitti. Retrieved 8 May 2020.
- S2CID 22285083.
- S2CID 23472006.
- ^ Müller, S. (2006). Diet composition of wolves (Canis lupus) on the Scandinavian peninsula determined by scat analysis (PDF) (Thesis). School of Forest Science and Resource Management, Technical University of München, Germany. Archived from the original (PDF) on 2016-03-04. Retrieved 2015-05-01.
- ^ Saniga, M. (2002). "Nest loss and chick mortality in capercaillie (Tetrao urogallus) and hazel grouse (Bonasa bonasia) in West Carpathians". Folia Zoologica-Praha. 51 (3): 205–214.
- ISSN 0003-455X.
- S2CID 90693193.
- .
- ISBN 978-0713665659.
- ISBN 978-0262220354.
- ^ Koryakin, A.S.; Boyko, N.S. (November 2005). The White tailed Sea Eagle Haliaeetus albicilla and the Common Eider Somate ria mollissima in the Gulf of Kandalaksha, White Sea. Proceedings of the Workshop, Kostomuksha. Status of Raptor Populations in Eastern Fennoskandia. Karelia, Russia. pp. 49–55.
- ^ "Capercaillie Life Project". Retrieved 2015-12-25.
Notes
External links
- Capercaillie mating game on the Internet Bird Collection
- Capercaillie at RSPB Birds by Name
- Aigas Field Centre Capercaillie Ecology and breeding programme pages
- Western Capercaillie—pictures in nature photographer Janne Heimonen's photo gallery
- BirdLife species factsheet for Tetrao urogallus
- "Tetrao urogallus". Avibase.
- "Western capercaillie media". Internet Bird Collection.
- Western capercaillie photo gallery at VIREO (Drexel University)
- Interactive range map of Tetrao urogallus at IUCN Red List maps
- Audio recordings of Western capercaillie on Xeno-canto.