Black grouse

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Black grouse
Black Grouse and Black Grouse (Lyrurus tetrix)

Black Grouse and Black Grouse ( Lyrurus tetrix )

Systematics
Order : Chicken birds (Galliformes)
Family : Pheasants (Phasianidae)
Subfamily : Grouse (Tetraoninae)
Genre : Black grouse ( Lyrurus )
Type : Black grouse
Scientific name
Lyrurus tetrix
( Linnaeus , 1758)

The black grouse ( Lyrurus tetrix , Syn. : Tetrao tetrix ) is a bird art from the family of pheasant-like (Phasianidae). Within this family it is one of the grouse , which, according to a classification that is now obsolete, used to form its own family, Tetraonidae .

The black grouse is a breeding bird of the boreal and subarctic forest zones as well as corresponding (sub) alpine and post- glacial landscapes from Great Britain to Eastern Siberia.

description

With a body length of 45–60 cm, the black grouse is one of the medium-sized grouse. The rooster reaches a body length of 55-60 cm. Its wing length is 246–291 mm, the tail length 173–219 mm and the weight between 820 and 1750 g. The hen is about 45 cm in length, a wing length of 214-263 mm, a tail length of 113-131 mm and a weight between 750 and 1120 g smaller and lighter. The sexes also differ significantly in the plumage color. While the rooster has a contrasting blue-black and white color, the hen shows brownish camouflage-colored plumage. Both sexes have white wing bands (= mirrors ) that can be seen in flight. The plumage is very dense and includes the nostrils and feet to the base of the toes. The barrel is long and dense in winter, with short feathers only on the front in summer. The iris is brown. The short and strong beak is horn black and the feet are brownish.

male

Black grouse

In the rooster there is a featherless, crescent-shaped and intensely red spot above the eye, which swells strongly during the mating season, so that the protrusions ("roses") almost touch each other over the top. They are covered with fine, platelet-like pencils and warts. The plumage is predominantly black in the magnificent dress and darkest on the neck and chest. Head, neck and the back part of the back shine steel blue and shimmer violet - on the head it is sometimes more greenish. The other parts of the body have a duller shine. The front part of the back, the shoulder plumage, the upper wing and upper tail coverts are brown-black and only show blue-black hems on the front back. A few white areas contrast with the black areas, such as the under wing coverts and the axillary feathers, which are visible as a cherry-sized, white spot in the shoulder area even when the wing is on. In addition, the basal two thirds of the arm wings and the bases of the inner hand wings are white and form a characteristic wing band. The bases of the large hand and arm covers as well as the wing are white, so that the folded wing shows a double band. The whitish shafts stand out optically on the black-brown hand wings. The white under-tail-coverts, which are longer than the central control feathers, are particularly noticeable in courting birds . Some of them have a black lace hem. The characteristic, lyre-shaped forked tail consists of 18 black feathers with a blue-violet to blue-green metallic sheen. The three, more rarely four outer pairs are curved outward in a sickle shape and stepped in length, the middle ones are shorter and partly lined with gray-white ends.

In the resting dress between June and August, brownish banded or scrawled feathers and whitish feathers on the chin and throat appear on the neck and partly on the front back and crown. Annual roosters often show more of these mottled feathers. In addition, the control springs will not have their full length before late winter.

female

Black hen

The hen's plumage is predominantly rust-brown on the upper side and is banded black-brown by wide subterminal bands. On the back of the back the blackish banding shows a blue metallic sheen. Especially on the anterior back, rump and most of the upper wing coverts, the feathers are partly greyishly lightened and scrawled black. The sides of the head and throat are more rusty beige and more finely banded, the goiter area is intensely rusty brown and heavily banded. The feathers on the rest of the underside show whitish, black-scribbled end bands, especially on the chest and belly. The banding is more open on the chest and condenses to the flanks and the under tail-coverts, which are broadly lined with white. The wings have a whitish lace border. Those of the hand wing are dark brown with rust-red speckles, the inner two-thirds of the arm wings are white on the basal two-thirds, so that they form a wing band like the rooster. The dark brown, distal third of the arm swing is heavily speckled. The under wing coverts are white. The black-brown control feathers are banded with rust-brown, scribbled with roughly rust-brown and lined with gray-beige. The tail is slightly forked.

distribution

Black grouse when belaying

The species area of ​​the black grouse in the Eurasian Palearctic extends almost over the entire forest and forest steppe zone and partially extends into the steppe zone. The closed distribution area begins in southeastern Poland and continues between the 50th and 70th parallel to eastern Siberia. With the exception of the mountain ranges and the tree-free tundra in the north and south of Sweden, Scandinavia is almost completely populated. With the exception of the Alpine region, the area in Central Europe is split up like islands. There are some residual deposits. a. in Germany (see below), the Netherlands, Belgium, Denmark and Great Britain (here especially in Scotland, in parts of northern England and in a narrow strip as far as Wales).

In Germany and near the border with Germany it can still be found in some alpine regions and in places in the following low mountain range regions : Rhön , Hohes Venn , Bavarian Forest / Bohemian Forest , Thuringian Forest , Thuringian Slate Mountains , Ore Mountains , Jizera Mountains , Giant Mountains . One occurrence exists in the triangle of Saxony-Brandenburg-Poland in the sandy heath area of ​​the Zschornoer Wald.

In the northwestern German lowlands, where the black grouse was still very common at the beginning of the 20th century, the populations have died out almost everywhere. For a long time, the black grouse was particularly numerous in the heather and moor areas of the Emsland and the county of Bentheim. Due to the massive changes in habitat, possibly also due to diseases, they have been extinct in the Bentheimer Land since 1978, in the Emsland since the late 1980s. Only in the Lüneburg Heath natural area do different areas still offer suitable habitats due to their structure, size and remoteness: The Bergen military training area , the Munster North and South military training areas , the Lüneburg Heath nature reserve , the Kiehnmoor and the Great Heath near Unterlüß (in the southern heath ) housed in 2004 most of the black grouse in Lower Saxony.

Habitats

Habitat in the Lüneburg Heath
Rich in plant remains : Black grouse “ Gestüber ”

Black grouse are typical inhabitants of the “fighting zones” of the forest (e.g. on the edges of bogs or in the mountains). They tend to inhabit open landscapes, loosely interspersed with bushes and trees. There they make very complex demands on the habitat over the course of the year: For courtship, wide, open and short-growing to vegetation-free areas (e.g. young heaths) are required. Half-open areas (e.g. bushy heaths) with a higher herbaceous layer are important for the brood. The chicks find their food on areas that are more nutrient-rich (e.g. fallow fields). Trees provide food in winter and bogs in spring. Typical habitats are / were moors and heather areas, semi-open (meadow) landscapes in the hill country and in light ridge forests of the low mountain ranges. In the Alps, the mountain pine, dwarf shrub, mat and alpine meadow regions are populated.

nutrition

The chicks and adult black grouse in the moult live on animal food (insects and other invertebrates), and young cocks in autumn also eat insect food. Otherwise, black grouse feed on changing plant species and parts over the course of the year. In spring, young shoots and buds as well as inflorescences of willows and some grasses (cotton grass) are mainly eaten. In summer, flower-filled meadows offer a varied diet. In autumn, the berries of dwarf shrubs ( crowberry , blueberry , lingonberry ) make up a large part of the diet, and the fruits of mountain ash, whitebeam and hawthorn are also consumed. The main food in winter is the buds and shoots of deciduous and coniferous trees.

Reproduction

Black grouse on a 1965 postage stamp
Black Grouse Egg ( Lyrurus tetrix tetrix )
Gelege, Museum Wiesbaden collection

The polygamous black grouse perform their courtship dances from March / April to June . These take place in traditionally used courtship areas, which are characterized by low vegetation and a clear view. Several roosters have ritualized exhibition fights there. In this group courtship, the oldest and highest-ranking animals occupy the centers of the courtship arenas. The individual roosters move in small individual territories with ruffled tail feathers and their bodies leaning forward, making alternating "rolling" and hissing sounds. Threatening poses are taken, but there is no fighting.

The hens initially observe these demonstrations from elevated positions (bushes, trees) on the edge of the courtship arena. Later they go to the courtship territory of the rooster of their choice or the strongest rooster. Soon after mating, the roosters continue their exhibition fights and court other females. The roosters linger on the courtship grounds until June. Even later, courtship dances and pairings can occasionally be observed. The roosters do not differentiate between black hens and similar hens from other fowl birds. If they occur together, mismatches and hybridizations, e.g. B. come with capercaillie and pheasant . Hybrids between capercaillie and black grouse are known as rackel fowl .

Hunting names such as "play cock" or "black knight" refer to courtship behavior.

The nest is created on the ground as a shallow hollow and is often hidden under dwarf shrubs or tufts of grass. From the end of April to May, in the high mountains from the end of May, usually 7-10 eggs are laid in this. The eggs are pale yellow to brown in color and mottled yellow to brown. The clutch is only incubated by the hen, after 24–28 days the chicks hatch and after 15–20 days they are able to fly. The chicks are fleeing nests and initially feed on animal protein (insects, worms), from a few weeks old they take on vegetable food.

Their survival depends to a large extent on the weather, warm and dry summers are favorable, and numerous chicks perish in cold and rainy weather. In September the families of hens and juveniles break up. Then the autumn balz begins, where the older roosters demonstrate their rank and fly with the young roosters from courtship to courtship and get to know large parts of the habitat. Pullets, on the other hand, have a rather small radius of action and stay with the old hens. Individual young birds migrate from the population in autumn.

Protection and exposure

In the European Union , the black grouse, like all domestic bird species, is protected under the Birds Directive . Special protected areas are to be designated to preserve the species. (Bird sanctuary in the Natura 2000 area network).

Protection, species-appropriate care (habitat management) and new development of habitats are the most important contributions to the protection of black grouse. Disturbances can e.g. This can be avoided or limited, for example, by directing visitors (routes not through sensitive areas, e.g. courtship areas) and prohibiting disruptive activities (e.g. model flying). The release of pheasants should be avoided to avoid interspecific competition.

Black grouse in the Lüneburg Heath

Germany

Occurrence

As a result of extensive losses and changes in habitats (e.g. peat removal or drainage of moors, loss of heathland and open spaces in forests), the black grouse stocks in Germany were destroyed with the exception of a few remains. These occurrences are endangered by increasing isolation or further downsizing of the habitats. Free-roaming dogs, the use of drones such as multicopters and, in particular, increasing winter activities in the area of ​​the tree line (light forest with shrub vegetation) can lead to considerable disruptions. In 2010 the population was estimated at around 2,000 animals, by 2017 it had fallen by almost half to 1,200 individuals.

80 percent of the German black grouse live in the Alps in the area of ​​the tree line. The black grouse is also threatened with extinction in Bavaria . The populations there have shrunk more massively than in the other German populations. The expansion of tourism and non-observance of the protected areas established by the Alpine Association are increasing the burden on the ailing populations. The number of black grouse has decreased by 60 percent in some regions since 2002. The intended change in the zoning of the Alpine plan by the Bavarian State Government would have unforeseeable consequences , especially for the population on the Riedberger Horn . If it is not possible to sensitize Bavarian politicians and tourists in particular to the problem and not keep commercial aspects in the foreground, this animal species will be extinct in Bavaria in the foreseeable future.

The lowland occurrence in the Lüneburg Heath and thus the population in Lower Saxony has fluctuated between 160 and 230 animals in the last ten years (as of 2011). In 2017, around 200 black grouse lived in the Lüneburg Heath nature reserve . The primary goal of the Landesjägerschaft Niedersachsen eV is to network the population, which is split into five larger and four smaller sub-populations, and to secure it by hunting predators and developing visitor management concepts.

For Saxony it is assumed that there are around 50 black grouse. In 2016, 25 courting roosters were counted in the Saxon part of the Ore Mountains (2018: 15) and 170 courting roosters on the Czech side. A species aid program is intended to help preserve the cross-border Czech-German Erzgebirge population. Since 2010 around 350 hectares of moors have been revitalized and around 220 hectares of forest cleared. As in Lower Saxony, the habitats in Saxony are not contiguous, which is why cooperation with the Czech side is particularly important.

The smallest occurrence of the black grouse in Germany is in the Rhön . Here the population was almost extinct at times, despite many years of protective measures. In 2007 only nine roosters and five hens were counted here. An extinction of the stock was predicted because the reproductive success did not materialize. For the first time in 2013, breeding success with three young birds was proven. After 68 Swedish black grouse were released into the wild, the number of black grouse in the Rhön rose for the first time in years through natural reproduction. The 2014 autumn census counted 14 cocks and 11 hens, including nine young birds. Through negotiations with the Swedish National Agency for Nature Conservation, imports of 25 animals per year can be secured for 2016-2020. The aim is to achieve a long-term viable black grouse population of 100 birds, for which the current habitat must be increased from 1,200 hectares to 5,000 hectares.

Black hen in flight
Black grouse in flight

The population in Baden-Württemberg has been extinct since 1978. From 1978 to 1992 attempts to reintroduce citizenship took place in the Wurzacher Ried , which failed.

National protection status

The black grouse, the bird of the year 1980, has been one of the animal species strictly protected under the Federal Nature Conservation Act since 2002 . Therefore, it is already a criminal offense to deliberately and significantly disturb wild black grouse during their breeding or rearing season ( Section 44 (1) no. 2 , 69 (2) no. 2 , Article 71 (a) no. 1 BNatSchG) ).

hunt

With the exception of Slovenia and Germany, black grouse hunting is permitted in the Alpine countries. Hunting ceased in Slovenia in 1993. In Germany, the black grouse is subject to the Federal Hunting Act , but with a year-round closed season and the associated duty of care for the hunters.

In France the population is decreasing. In the French Alps from 1999 to 2002 1,040 cocks were shot out of an estimated 20,000 individuals total population. For the year 2009 a population of 16,600 adult birds was determined, which corresponds to a decrease of 11 percent compared to the previous decade.

In Austria , the stock is reported as stable. The kill in Austria is around 1,500 roosters annually with a population of around 26,000 individuals (2007). With 530 kills, Tyrol had a share of 36 percent.

In 2004, around 15,000 to 20,000 individuals lived in Switzerland . Over 500 black grouse were shot here annually, and since 2008 around 400 black grouse. Since 2014 the hunting range has been around 550 roosters. With the exception of five cantons, black grouse has been hunted, most recently in the canton of Uri from 2001. The hunt for black grouse is essentially limited to the cantons of Valais , Ticino and Graubünden . As in Bavaria, increasing tourism in Switzerland, even in remote regions, poses a serious threat to individual populations. Conservationists are calling for a reduction in hunting pressure on the black grouse. At the northern limit of distribution as well as at the southern border, Ticino , the population has been decreasing since the 1980s.

Regular inventory surveys, the creation of connections between the individual populations, so-called stepping stone concepts and habitat improvements (e.g. through hunting tenants, continued alpine pasture management ) can make a significant contribution to species conservation. Since hens travel distances between 5 and 35 km, it is important that roosters that are true to their location are replaced in stepping stone habitats that are no longer occupied. Black grouse do not form pairs, so shooting is largely restricted to roosters, while hens are protected all year round.

Red List

Red list classifications (selection):

  • Germany: Category 1 (critically endangered)
  • Switzerland: NT (Near Threatened = low risk, warning list)
  • total: LC (Least Concern = not at risk)

Subspecies

Different authors usually describe 6–8 subspecies of the black grouse, whereby the selection of the individual subspecies usually differs somewhat.

As generally recognized, in addition to the nominate form L. t. tetrix also L. t. britannicus, L. t. ussuriensis, L. t. viridanus and L. t. mongolicus apply.

Black grouse subspecies, distribution and characteristics according to The Internet Bird Collection and Stegemann 1932:

Lyrurus tetrix baikalensis ( Lorenz , 1911)

SE Siberia, from Lake Baikal to Amur , Mongolia and western Manchuria
Characteristics: males shimmering greenish, head mostly brownish, speckled drawing, large mirror, large animals

Lyrurus tetrix britannicus Witherby & Lonnberg , 1913

Northern and Western Great Britain
Characteristics: very dark colored, males with z. T. purple shimmer, mirror and other white parts of the plumage opposite L. t. tetrix reduced.

Lyrurus tetrix mongolicus ( Lonnberg , 1904)

Kyrgyzstan , Tian Shan to Altai and other regions of western Mongolia
Characteristics: males shimmer in pure blue, females are drawn relatively dark and finely blurred, large mirror, large subspecies

Lyrurus tetrix tetrix ( Linnaeus , 1758)

Large parts of the distribution area, from Scandinavia, Belgium, the southern French Alps to northeastern Siberia
Features: see above

Lyrurus tetrix ussuriensis ( Kohts , 1911)

Eastern Manchuria up to the Ussuri and probably also the Amur
Characteristics: males with a pronounced green metallic sheen, very large mirror, females rust-brown, birds larger than L. t. tetrix , but smaller than L. t. baikalensis

Lyrurus tetrix viridanus ( Lorenz , 1891)

SO Russia and SW Siberia, between Don and Irtysh
Characteristics: males with a greenish-blue metallic sheen, females light-colored, white mirror significantly larger than in L. t. tetrix , plumage partially speckled

Lyrurus tetrix tschusii ( Johansen , 1898)

South of Siberia, from Irtysh to Lake Baikal , north to Tomsk and Krasnoyarsk, in the south to NW Altai and the Sayan Mountains

symbolism

Black grouse symbol in the Hohes Venn-Eifel nature park
  • In 1940/41 the 97th Jäger Division was formed from locals in Bad Tölz and the surrounding area . A feather from the Spielhahn was used as the tactical departmental symbol of the division, which gave rise to the nickname Spielhahnjäger .

literature

  • Urs N. Glutz von Blotzheim , Kurt M. Bauer: Handbook of the birds of Central Europe , Volume 5, Galliformes - Gruiformes. Aula-Verlag, Wiesbaden, 2nd edition 1994: pp. 322-370, ISBN 3-923527-00-4 , pp. 105-172
  • Siegfried Klaus, Hans-Heiner Bergmann , Christian Marti et al .: The black grouse. (= Die Neue Brehm-Bücherei. Volume 397). A. Ziemsen Verlag, Wittenberg Lutherstadt 1990, ISBN 978-3-89432-397-4 .
  • Jann Wübbenhorst and Johannes Prüter : Basics for a species aid program "Black grouse in Lower Saxony" Nature conservation and landscape maintenance in Lower Saxony, issue 42 (2007). ( Table of Contents & Summary )
  • Helmut Lensing: The black grouse (Tetrao tetrix left) in the Grafschaft Bentheim and in the Emsland - Has the "black knight" disappeared forever ?, in: Study Society for Emsländische Regionalgeschichte (ed.): Emsländische Geschichte 21, Haselünne 2014, p. 123-171.
  • Heinz-Sigurd Raethel : Chicken birds of the world. Verlag J. Neumann-Neudamm GmbH & Co. KG, Melsungen 1988, ISBN 3-7888-0440-8 , pp. 250-257.
  • Steve Madge, Phil McGowan : Pheasants, Partridges & Grouse. Helm Identification Guides, Christopher Helm, London 2002, ISBN 0-7136-3966-0 , pp. 368-369.

Web links

Commons : Black Grouse ( Lyrurus tetrix )  - Album with pictures, videos and audio files

Individual evidence

  1. ↑ Hans-Günther Bauer, Einhard Bezzel and Wolfgang Fiedler (eds.): The compendium of birds in Central Europe: Everything about biology, endangerment and protection. Volume 1: Nonpasseriformes - non-sparrow birds , Aula-Verlag Wiebelsheim, Wiesbaden 2005, ISBN 3-89104-647-2
  2. ↑ Dimensions according to Madge, p. 369 and Raethel, p. 251, s. literature
  3. ↑ Glutz v. Blotzheim, p. 110, p. literature
  4. ↑ Raethel, p. 251, s. literature
  5. ↑ a b Roland Lehmann: Species Protection Program Black Grouse, 2000. Ed .: Ministry for Agriculture, Environmental Protection and Regional Planning of the State of Brandenburg (MLUR) Franckh, brochure, 48 pp.
  6. ↑ a b IUCN, s. Web links
  7. ↑ Johannes Prüter, Jann Wübbenhorst Peter Südbeck: Lower Saxony's responsibility for the conservation of the black grouse ( Tetrao tetrix ) in the Central European lowlands. - Vogelkdl. Ber. Lower Saxony. 36: 121-130 (2004).
  8. ↑ a b c d e NaturSportInfo from the Federal Agency for Nature Conservation ( Memento from July 21, 2011 in the Internet Archive ) (accessed on February 11, 2011)
  9. ^ Manfred Lütkepohl: Birds. In: Cordes et al .: Lüneburger Heide nature reserve, 1997 Verlag M. Hauschild, ISBN 3-931785-36-X
  10. ↑ a b Einhard Bezzel: Vögel, Volume 2, 1984 BLV, ISBN 3-405-12877-3
  11. ^ A b Saxon State Ministry for the Environment and Agriculture (2010): Birkhuhn / Tetrao tetrix. - Biodiversity in Saxony, brochure, 24 pp.
  12. ↑ a b NLWKN (Hrsg.) (2011): Implementation instructions for the protection of breeding bird species in Lower Saxony. - Value-determining breeding bird species in bird sanctuaries with the highest priority for conservation and development measures - Black grouse ( Tetrao tetrix ). - Lower Saxony strategy for species and biotope protection, Hanover, 8 p., Unpublished.
  13. ↑ Süddeutsche Zeitung : The locals don't like the hype , accessed on July 29, 2017.
  14. ↑ LBV : A clear majority does not want a ski swing ( memento from July 30, 2017 in the Internet Archive ), accessed on July 29, 2017.
  15. ↑ Joint statement regarding the zoning of the Alpine plan , accessed on July 29, 2017.
  16. ↑ RETTET DAS RIEDBERGER HORN , accessed on July 29, 2017.
  17. ^ Landesjägerschaft Niedersachsen eV: Black grouse in Lower Saxony , May 29, 2017, accessed on July 29, 2017.
  18. ^ State enterprise Sachsenforst: Species aid program for black grouse in the Ore Mountains ( memento of July 30, 2017 in the Internet Archive ), March 27, 2017, accessed on July 29, 2017; about this and the current development: Sächs. State Office for Environment, Agriculture and Geology : Black grouse species protection program for the Free State of Saxony , July 31, 2019.
  19. ↑ Eckhard Jedicke: Nature conservation in the Rhön biosphere reserve - model landscape or developing country In: Yearbook Nature Conservation in Hessen. Volume 12, 2008, pp. 33-37.
  20. ↑ Rhön Biosphere Reserve : The Black Grouse in the Rhön , accessed on July 29, 2017.
  21. ^ NABU : Vogel des Jahres 1980
  22. ^ Scientific information system for international species protection (WISIA). Federal Agency for Nature Conservation , accessed on March 23, 2020 (protection status is indicated by entering the term “black grouse”). Protection by listing in Appendix 1 (to Section 1) of the Federal Species Protection Ordinance (BArtSchV)
  23. ↑ Black Grouse. Retrieved June 19, 2019 .
  24. ↑ § 2 para. 1 no. 2 Federal Hunting Act (BJagdG)
  25. ↑ Le Tétras-lyre , French, accessed July 29, 2017.
  26. ↑ Current population figures for Austria could not be determined. The only federal state in which black grouse counts are carried out on a regular basis appears to be Vorarlberg .
  27. ↑ According to the information, stocks in Switzerland should be stable, reliable figures are not available. The stock number from 2004 was never changed until 2017.
  28. ↑ Federal Hunting Statistics , accessed on July 30, 2017.
  29. ↑ Senseless killing of the threatened Ptarmigan , accessed on July 30, 2017.
  30. ↑ a b Wildauer / Schreiber / Reimoser: EU Birds Directive: Black Grouse , accessed on March 18, 2019 (PDF document; 534 kB)
  31. ↑ Christoph Grüneberg, Hans-Günther Bauer, Heiko Haupt, Ommo Hüppop, Torsten Ryslavy, Peter Südbeck: Red List of Germany's Breeding Birds , 5 version . In: German Council for Bird Protection (Hrsg.): Reports on bird protection . tape 52 , November 30, 2015.
  32. ↑ vogelwarte.ch, accessed on February 14, 2011
  33. ↑ http://data.iucn.org/dbtw-wpd/edocs/2007-034.pdf * IUCN: Grouse - Status Survey and Conservation Action Plan 2006-2010
  34. ↑ https://avibase.bsc-eoc.org/species.jsp?lang=DE&avibaseid=D4441CD6E9C993EF Lyrurus tetrix at Avibase
  35. ↑ Archive link ( Memento from December 9, 2014 in the Internet Archive ) Global Biodiversity Information Facility
  36. ↑ http://ibc.lynxeds.com/species/eurasian-black-grouse-tetrao-tetrix The Internet Bird Collection
  37. ↑ B. Stegemann (1932): The geographical forms of the black grouse (Lyrurus tetrix L.). Journal of Ornithology 80: 342-354.
  38. ^ The Internet Bird Collection
  39. ↑ B. Stegemann (1932): The geographical forms of the black grouse (Lyrurus tetrix L.). Journal of Ornithology 80: 342-354.