Hazel Grouse Tetrastes bonasia Scientific name definitions

35–40 cm; male 305–430 g, female 307–422 g (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ). In E Siberia might be confused with <em>Falcipennis falcipennis</em> , which lacks any crest, the broad white malar  , whitish shoulder stripe and whitish ground colour to scalloped underparts, all of which are features of present species (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ). Variably brownish grey, with fine dark barring on crown, neck, mantle and uppertail-coverts  ; underparts  barred or spotted with dark grey and ochre; chin black, bordered with white; white lines below and behind eyes, and on sides of neck; tail  relatively long and rounded, white-fringed, with a black subterminal band, broken by all-brown central pair of rectrices. Small erectile crest; small red combs  ; greyish-black bill. Male has drabber eclipse plumage (Jul–Sept) with duller head pattern and black throat  obscured by whitish feather fringes (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ). Female brownish , with whitish throat . First-winter almost identical to adult, with some minor differences in two outermost primaries, i.e. young birds exhibit more bars on these feathers (2 Swenson, J.E. (1992). Relative Alterbestimmung bei adulten Haselhühner (Bonasa bonasia). Journal of Ornithology. 133(2): 209–212. Close ); juvenile (plumage short-lived) (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ) like adult female, with whitish throat and more rufous upperparts with white or buffy shaft-streaks on back, and lacks white scapular spots and blackish subterminal tailband (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ). Races differ mainly in size and intensity of grey and brown tones (two colour morphs often recognized), with some individual variation observed in SE Europe, and clinal variation involving larger and greyer populations in N Scandinavia and Russia, versus tawny-coloured birds further S, which in turn become richer-coloured from E to W (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ).

Editor's Note: This article requires further editing work to merge existing content into the appropriate Subspecies sections. Please bear with us while this update takes place.

Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Mostly occurs in mixed coniferous deciduous woodland, with well-developed understorey , both in plains and mountains, up to 1600–1800 m in Alps; in Norway, is specialized on middle-aged decidous-rich coniferous forest (5 Gregersen, F. and Gregersen, H. (2009). Ongoing population decline and range contraction in Norwegian forest grouse. Ornis Norvegica. 32: 179–189. Close ), with typical trees being Norway spruce (Picea abies, Pinaceae), Scots pine (Pinus sylvestris, Pinaceae), the birches Betula pubescens and B. pendula (Betulaceae), and other deciduous trees including Populus tremula (Salicaceae), Alnus glutinosa, A. incana (Betulaceae), Salix caprea (Salicaceae), Sorbus aucuparia and Prunus padus (Rosaceae) (6 Swenson, J.E., Andreev, A.V. and Drovetskii, S.V. (1995). Factors shaping winter social organization in Hazel Grouse Bonasa bonasia: a comparative study in the eastern and western Palearctic. Journal of Avian Biology. 26(1): 4–12. Close ). Favours second growth in NE China, despite that mortality is apparently higher in such areas versus mature forest (7 Yue-Hua, S. and Yu, F. (1994). Winter habitat selection and analysis of Hazel Grouse in the Changbai Mountains. Journal of Ornithology. 135(1): 191. Close ), but probably cannot adapt to relatively small ‘islands’ of forest, at least in Europe (8 Aberg, J. (1994). Effects of habitat patch size and isolation on Hazel Grouse Bonasa bonasia occurrence in two fifferent landscapes. Journal of Ornithology. 135(1): 231. Close ). Habitat varies in different parts of extensive range, but species seems to avoid pure coniferous stands, and occurs in areas without conifers, e.g. parts of W Europe and mountainous regions of N Mongolia and Transbaikalia, while in South Korea is regularly found in planted Japanese larch (Larix leptolepis) forests (9 Rhim, S.-J. and Lee, W.-S. (2001). Characteristics of hazel grouse Bonasa bonasia distribution in southern Korea. Wildl. Biol.. 7: 257–261. Close ), but also shows some seasonal shifts, with, in C Europe, preference for denser, middle-aged forests in winter and more open-structured and younger areas in summer (10 Kämpfer-Lauenstein, A. (1997). Habitat selection of hazel grouse Bonasa bonasia and natural dynamics in different central European woodland associations. Wildl. Biol.. 3(3–4): 289. Close ). Large, dense forests with rich, varied undergrowth (up to c. 2 m tall) (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ) and occasional clearings are generally preferred, as are presence of thickets of alder (Alnus)—the single most important woody plant (11 Swenson, J.E. (1994). The central role of winter food (alder) in the life of Hazel Grouse. Journal of Ornithology. 135(3): 263. Close )—as well as birch (Betula), aspen (Populus), hazel (Corylus, Betulaceae) and other catkin-bearing trees; along streams and rivers, in transitional areas or in clearings caused by fires, avalanches or lumbering, but never in truly open areas (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ). In Swiss Alps, prefers forests with large proportions of alder and diverse mosaic of canopy closure and stand structure, with many tall Sorbus aucuparia trees, edges and a dense shrub layer at the micro-scale (12 Schäublin, S. and Bollmann, K. (2011). Winter habitat selection and conservation of Hazel Grouse (Bonasa bonasia) in mountain forests. Journal of Ornithology. 152(1): 179–192. Close ).

Highly sedentary: in Russia, 88% of recoveries within 500 m of ringing site, maximum 1500 m; mean of 20 recoveries in Sweden and Finland, 1·2 km, maximum 10 km. Females and juveniles tend to disperse farther, but unpaired males frequently have larger territories (32·2 ± 2·8 ha versus 18·8 ± 2·4 ha) (13 Swenson, J.E. and Boag, D.A. (1993). Are Hazel Grouse Bonasa bonasia monogamous? Ibis. 135(4): 463–467. Close ) and significantly more prone to move (2·1–14·3 km) than paired males (13 Swenson, J.E. and Boag, D.A. (1993). Are Hazel Grouse Bonasa bonasia monogamous? Ibis. 135(4): 463–467. Close ), while territory sizes do not differ between sexes during summer, at least among birds that are paired (13 Swenson, J.E. and Boag, D.A. (1993). Are Hazel Grouse Bonasa bonasia monogamous? Ibis. 135(4): 463–467. Close ). Overall, territory size can be as large as 40 ha and as small as 8·3 ha (12 Schäublin, S. and Bollmann, K. (2011). Winter habitat selection and conservation of Hazel Grouse (Bonasa bonasia) in mountain forests. Journal of Ornithology. 152(1): 179–192. Close ); in South Korea, average home-range size of males is significantly larger than that of females, while home ranges of paired and single individuals are significantly smaller than those of individuals in flocks (14 Rhim, S.-J. (2010). Spring-season social organization of the Hazel Grouse (Bonasa bonasia) in relation to habitat type in temperate forests of South Korea. Ornis Fennica. 87: 160–167. Close ), with spring home range of females in SE French Alps prior to incubation 7·6–31·1 ha (15 Montadert, M. and Léonard, P. (2011). Biologie de la reproduction de la Gélinotte des bois Bonasa bonasia dans les Alpes-de-Haute-Provence (France) [Breeding biology of Hazel Grouse Bonasa bonasia in the southeastern French Alps]. Alauda. 79(1): 1–16; 79(2): 89–98. Close ). Study in China reported that young, on dispersing in autumn, move up to 5·7 km (16 Fang, Y. and Sun, Y.-H. (1997). Brood movement and natal dispersal of Hazel Grouse Bonasa bonasia at Changbai Mountain, Jilin Province, China. Wildlife Biology. 3(3–4): 261–264. Close ), while in SE French Alps mean dispersal distance between capture sites of juveniles in Sept–Oct and centre of home range in following spring is 4 km for males (range 0·1–24·9 km) and 2 km for females (range 0·2–5·6 km) (17 Montadert, M. and Léonard, P. (2006). Post-juvenile dispersal of Hazel Grouse Bonasa bonasia in an expanding population of the southeastern French Alps. Ibis. 148(1): 1– 13 Close ). In winter birds typically roost in snow burrows, but in regions with a more maritime climate they use trees, especially Norway spruce (Picea abies) in one Swedish study (18 Swenson, J.E. and Olsson, B. (1991). Hazel Grouse night roost site preferences when snow-roosting is not possible in winter. Ornis Scandinavica. 22: 284–286. Close ). In South Korea, there is evidence of elevational movements, descending in winter (9 Rhim, S.-J. and Lee, W.-S. (2001). Characteristics of hazel grouse Bonasa bonasia distribution in southern Korea. Wildl. Biol.. 7: 257–261. Close ).

During winter almost exclusively catkins, buds  and twigs of alder, birch or both; also hazel, aspen, etc.; in study conducted in NE France, where some intra-seasonal variation noted with altitude, most important species at this season are Carpinus betulus, Corylus avellana (Betulaceae), Sorbus aria and S. aucuparia (Rosaceae) (19 Schatt, J. (1993). Étude du régime alimentaire de la Gélinotte des bois dans l'Ain (deuxième partie). Alauda. 60(1): 19–34. Close ); in South Korea, buds and catkins of trees in the genera Salix, Betula and Alnus (20 Rhim, S.-J. and Lee, W.-S. (2003). Winter sociality of hazel grouse Bonasa bonasia in relation to habitat in a temperate forest of South Korea. Wildl. Biol.. 9: 365–370. Close ). In spring , these are gradually replaced by leaves of same trees, and, depending on snow conditions, leaves and flowers of ground vegetation; in NE Asia, at this season, winter foods decrease from 75% to 3%, whereas the proportion of berries increases from 6% to 70% and subsequently foliage forms up to 72% of diet (21 Drovetski, S.V. (1997). Spring social organisation, habitat use, diet, and body mass dynamics of hazel grouse Bonasa bonasia in northeastern Asia. Wildl. Biol.. 3: 251–259. Close ); patches of newly sprouted forbs are especially important (and defended) at this season (11 Swenson, J.E. (1994). The central role of winter food (alder) in the life of Hazel Grouse. Journal of Ornithology. 135(3): 263. Close ). Berries and other fruits important during summer and autumn, mainly those of Vaccinium (Ericaceae), but also Ribes (Grossulariaceae), Fragaria, Rubus, Sorbus, Crataegus, Prunus (Rosaceae) and others, varying considerably with region depending on availability, e.g. fruits of Viburnum sargenti (Adoxaceae) are strongly favoured in NE China (7 Yue-Hua, S. and Yu, F. (1994). Winter habitat selection and analysis of Hazel Grouse in the Changbai Mountains. Journal of Ornithology. 135(1): 191. Close ), while in NE France seeds of Carex sylvatica (Cyperaceae) are important in summer and fruits of Rubus idaeus and Crataegus sp. became important in autumn (19 Schatt, J. (1993). Étude du régime alimentaire de la Gélinotte des bois dans l'Ain (deuxième partie). Alauda. 60(1): 19–34. Close ). Chicks almost exclusively eat arthropods during first ten days, mainly ants and their larvae, but also beetles, caterpillars, grasshoppers and spiders; thereafter, become progressively more vegetarian. In autumn, nuts, acorns and seeds can be important, e.g. Carpinus, Acer (Sapindaceae), Quercus, Fagus (Fagaceae), conifers, etc. Daily food c. 41 g in winter, 58 g in spring, 28 g in summer, and 27 g in autumn. Sometimes forms flocks in winter (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ), of mixed sex (20 Rhim, S.-J. and Lee, W.-S. (2003). Winter sociality of hazel grouse Bonasa bonasia in relation to habitat in a temperate forest of South Korea. Wildl. Biol.. 9: 365–370. Close ), and extent and nature of this behaviour apparently determined by relative food adundance, which in turn is linked to habitat type, with flocks smallest (more commonly pairs, up to five individuals, mean 1·4) and least frequent in dense spruce forests in Sweden, intermediate in larch/birch ecotonal forests in E Siberia, and largest (up to 30 birds, mean 6·3) and most numerous in open deciduous riparian forests in E Siberia, where the birds form cohesive, mixed-sex flocks (6 Swenson, J.E., Andreev, A.V. and Drovetskii, S.V. (1995). Factors shaping winter social organization in Hazel Grouse Bonasa bonasia: a comparative study in the eastern and western Palearctic. Journal of Avian Biology. 26(1): 4–12. Close ). Group size larger in increasingly open forests with less cover but more winter food; the larger flock size may additionally assist in predator detection (6 Swenson, J.E., Andreev, A.V. and Drovetskii, S.V. (1995). Factors shaping winter social organization in Hazel Grouse Bonasa bonasia: a comparative study in the eastern and western Palearctic. Journal of Avian Biology. 26(1): 4–12. Close ).

Advertising call, given from prominent stump or rock, is a high-pitched whistle  , “(t)seeeeee-(t)see-(t)see”, repeated up to nine times and usually only audible only at very close range, but varies in length of notes and their pitch; wing-whirrs are audible up to 100 m away; and males also utter ‘challenge call’, “srit srit”, usually from a perch, in response to another male that enters its territory (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ). Playback of the advertising call is useful means of censusing the species (22 Desbrosses, R. (1996). Comparaison de deux méthodes de dénombrement d’une population de Gélinotte des bois Bonasa bonasia dans le Jura français. Alauda. 64(3): 293–306. Close ). Female calls  are lower-pitched and include a distraction call, a melodious “piih-tettettettett”, while both sexes give “plit plit” or “pitt pitt pitt” in alarm (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ).

Lays Apr–May in C Europe, May–Jun in Scandinavia and Siberia. Facultatively monogamous with male often guarding female rather than territory (21 Drovetski, S.V. (1997). Spring social organisation, habitat use, diet, and body mass dynamics of hazel grouse Bonasa bonasia in northeastern Asia. Wildl. Biol.. 3: 251–259. Close ), although pair-bond is apparently relatively weak (even in spring, further reduced in winter) and species may in fact exhibit some level of polyandry, at least in Scandinavia (while female territories do not overlap in breeding season, those of males do) (13 Swenson, J.E. and Boag, D.A. (1993). Are Hazel Grouse Bonasa bonasia monogamous? Ibis. 135(4): 463–467. Close ); male usually leaves territory during incubation. During male’s advertising display, calls and wing-whirring are accompanied by short jumps, tail-spreading and wing-drooping behaviours (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ); in W of range (e.g. Sweden), male remains territorial throughout winter, but not in E Siberia, where less time is available for feeding at this season but, at least locally, food is more abundant (6 Swenson, J.E., Andreev, A.V. and Drovetskii, S.V. (1995). Factors shaping winter social organization in Hazel Grouse Bonasa bonasia: a comparative study in the eastern and western Palearctic. Journal of Avian Biology. 26(1): 4–12. Close ). Nest (constructed by female alone) (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ) a shallow scrape, lined with grass, leaves and other plant material, well concealed by undergrowth or under roots of fallen tree. Lays 7–11 yellow-brown eggs usually slightly speckled red-brown (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ) (5–14, means 7·3 (15 Montadert, M. and Léonard, P. (2011). Biologie de la reproduction de la Gélinotte des bois Bonasa bonasia dans les Alpes-de-Haute-Provence (France) [Breeding biology of Hazel Grouse Bonasa bonasia in the southeastern French Alps]. Alauda. 79(1): 1–16; 79(2): 89–98. Close ), 7·6 (13 Swenson, J.E. and Boag, D.A. (1993). Are Hazel Grouse Bonasa bonasia monogamous? Ibis. 135(4): 463–467. Close ) and 8·9 (23 Jönsson, K.I., Angelstam, P.K. and Swenson, J.E. (1991). Patterns of life-history and habitat in Palaearctic and Nearctic forest grouse. Ornis Scandinavica. 22: 275–281. Close ) in three studies), laid at 1·3-day intervals (13 Swenson, J.E. and Boag, D.A. (1993). Are Hazel Grouse Bonasa bonasia monogamous? Ibis. 135(4): 463–467. Close ); incubation 23–27 (usually 25) days by female alone (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ); downy young  have brown crown cap not bordered by black; flight feathers present at or shortly after hatching; chicks capable of flight at c. 15 days and remain with female for up to 80 days (16 Fang, Y. and Sun, Y.-H. (1997). Brood movement and natal dispersal of Hazel Grouse Bonasa bonasia at Changbai Mountain, Jilin Province, China. Wildlife Biology. 3(3–4): 261–264. Close ). Females may re-nest if first clutch lost, perhaps with different male, but apparently initiates replacement clutches no later than 15 Jun in C Sweden (13 Swenson, J.E. and Boag, D.A. (1993). Are Hazel Grouse Bonasa bonasia monogamous? Ibis. 135(4): 463–467. Close ) and typically lays fewer eggs (15 Montadert, M. and Léonard, P. (2011). Biologie de la reproduction de la Gélinotte des bois Bonasa bonasia dans les Alpes-de-Haute-Provence (France) [Breeding biology of Hazel Grouse Bonasa bonasia in the southeastern French Alps]. Alauda. 79(1): 1–16; 79(2): 89–98. Close ). Mean brood size (when still dependent) 4·7 in one study. In NE China, reproductive success 20·9% and survival rate of chicks 37·5%; success was significantly negatively correlated with days of precipitation in Jun during young chick period, while parasitism by the tick Ixodes persulactus is principal cause of chick death (24 Piao, Z.-J. and Sun, Y.-H. (1998). Reproductive success of Hazel Grouse at Changbai Mountain. Ostrich. Pp. 332–333 in:. Close ). In E Europe (SW Finland and Poland) success most clearly governed by weather during pre-laying period, negatively correlated with precipitation and positively with temperature; the availability of nutritionally rich food to females during same period also deemed to be important in breeding success (25 Swenson, J.E., Saari, L. and Bonczar, Z. (1994). Effects of weather on Hazel Grouse reproduction: an allometric perspective. Journal of Avian Biology. 25(1): 8–14. Close ). Foxes and wild boar (Sus scrofa) may be important predators of nests (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ), while raptors, red foxes (Vulpes vulpes) or pine martens (Martes martes) account for most mortality of adults, at least regionally (27 Montadert, M. and Leonard, P. (2003). Survival in an expanding hazel grouse Bonasa bonasia population in the southeastern French Alps. Wildl. Biol.. 9: 357–364. Close ). First breeding at one year old. Annual adult survival rate probably c. 30%, but regionally reaches as high as 72% (males in SE Alps), with seasonal differences between sexes (27 Montadert, M. and Leonard, P. (2003). Survival in an expanding hazel grouse Bonasa bonasia population in the southeastern French Alps. Wildl. Biol.. 9: 357–364. Close ); one ringed bird survived seven years, three months.

Not globally threatened (Least Concern). Included on Red Data lists of China and several C & S European countries (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ). Marked declines and some range contraction in many parts of W & C Europe, apparently due to abandonment of traditional coppicing practices (28 Swenson, J.E. and Danielsen, J. (1991). Workshop summary: status and conservation of the Hazel Grouse in Europe. Ornis Scandinavica. 22: 297–298. Close ), e.g. extinctions in Massif Central and some lowland areas of Germany, with rapid declines in Belgium, Luxembourg (28 Swenson, J.E. and Danielsen, J. (1991). Workshop summary: status and conservation of the Hazel Grouse in Europe. Ornis Scandinavica. 22: 297–298. Close ) and Switzerland (29 Blattner, M. (1998). Der Arealschwund des Haselhuhns Bonasa bonasia in der Nordwestschweiz [The range loss of Hazel Grouse Bonasa bonasia in northwestern Switzerland]. Orn. Beob.. 95(1): 11–38. Close ), but recently (1980s) rediscovered in Pyrenees (30 Catusse, M. (1994). Hazel Grouse in the Pyrenees. British Birds. 87(6): 271–272. Close ), where mainly known from localities on French side of border (31 Catusse, M., Mothe, T. and Menoni, E. (1992). La Gélinotte des bois Bonasa bonasia existe dans les Pyrénées. Alauda. 60(3): 129–133. Close ). European populations: < 10,000 pairs in France (currently increasing locally) (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close , 32 Montadert, M. and Léonard, P. (2014). Sur le front de colonisation: la Gélinotte des bois Tetrastes bonasia dans les Alpes-Maritimes [Hazel Grouse Tetrastes bonasia is an expanding species in the southern part of French Alps (Alpes-Maritimes, France)]. Alauda. 82(1): 19–26. Close ), 5000–6000 in Italy (where spreading and perhaps increasing) (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ), c. 200 in Belgium, 1000–1500 in Germany (where still declining and true numbers may be much smaller) (33 Gedeon, K., C. Grüneberg, A. Mitschke, C. Sudfeldt, W. Eikhorst, S. Fischer, M. Flade, S. Frick, I. Geiersberger, B. Koop, M. Kramer, T. Krüger, N. Roth, T. Ryslavy, S. Stübing, S. R. Sudmann, S. Steffens, F. Vökler, and K. Witt (2014). Atlas Deutscher Brutvogelarten [Atlas of German Breeding Birds]. Stiftung Vogelmonitoring Deutschland und Dachverband Deutscher Avifaunisten, Münster, Germany. Close , 34 Lieser, M. (2015). Wo gibt es noch Haselhühner in Deutschland? [Where in Germany do we still have Hazel Grouse?] Vogelwarte. 53(2): 155–156 Close ), 4500–6000 in Romania (35 Kalabér, L.V. (1998). The status of the Capercaillie Tetrao urogallus, Hazel Grouse Tetrastes bonasia and Black Grouse Lyrurus tetrix in Romania. Ostrich. P. 291 in:. Close ), c. 30,000 in Estonia, c. 150,000 in Sweden  , and c. 230,000 in Finland; generally much more numerous eastwards, but very rare in Ukraine, where occurs only in Poles’ye zone and Carpathians, with highest density of c. 2 pairs/km². Habitat degradation is most potent of current threats in NE China, with illegal hunting apparently much reduced (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ). Declined rapidly in Japan during 1970s coinciding with sharp increase in numbers of red foxes (Vulpes vulpes) (1 Madge, S., and P. McGowan (2002). Pheasants, Partridges and Grouse, including Buttonquails, Sandgrouse and Allies. Christopher Helm, London, UK. Close ); sport hunting there claimed 50,000 birds in late 1960s, but just 5000 in 1991 and < 1000 by 2003 (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ). Most important natural predator throughout species’ range is Northern Goshawk (Accipiter gentilis) (6 Swenson, J.E., Andreev, A.V. and Drovetskii, S.V. (1995). Factors shaping winter social organization in Hazel Grouse Bonasa bonasia: a comparative study in the eastern and western Palearctic. Journal of Avian Biology. 26(1): 4–12. Close ). Abundance varies markedly between years, with climatic variables perhaps lying at root of these, especially mean temperature and total precipitation in Apr (highly significant positive correlations) and mean temperature and total precipitation in May and Sept (significant negative correlations) (36 Klaus, S. (2007). A 33-year study of hazel grouse Bonasa bonasia in the Bohemian Forest, Šumava, Czech Republic: effects of weather on density in autumn. Wildl. Biol.. 13(Suppl. 1): 105–108. Close ), although in some areas cyclic changes have since vanished (37 Lampila, P., Ranta, E., Mönkkönen, M., Lindén, H. and Helle, P. (2011). Grouse dynamics and harvesting in Kainuu, northeastern Finland. Oikos. 120: 1057–1064. Close ). Spring densities in Switzerland range from c. 2 pairs/km² in lowlands to > 5 pairs/km² in forests above 1000 m; up to 30 birds/ha in a mixed forest in Poland. Autumn densities in N European mixed forests usually average 4·6–37 birds/km²; in C European montane forests 10–11 birds/km². Hunting (often aided by use of special whistles that imitate species’ vocalizations) (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ) not generally likely to affect populations, given its secretive habits; some annual bag figures during 1970s include c. 10,200 birds in Norway (where population has declined, also in response to modern forestry practices and climate change) (5 Gregersen, F. and Gregersen, H. (2009). Ongoing population decline and range contraction in Norwegian forest grouse. Ornis Norvegica. 32: 179–189. Close ), c. 18,000 in Sweden and 28,000–69,600 in Finland, but more intensively hunted (using snares and traps) (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ) in European Russia and Siberia, where perhaps as many as 2,000,000 birds/year taken during early 1990s (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ), and poaching may be significant in Korea (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ). Apparently very sensitive to habitat changes, especially modern forestry trends, although small-scale timber work could have positive effects, as could permitting natural reforestation of areas subject to natural events such as avalanches, insect calamities, fires and erosion (12 Schäublin, S. and Bollmann, K. (2011). Winter habitat selection and conservation of Hazel Grouse (Bonasa bonasia) in mountain forests. Journal of Ornithology. 152(1): 179–192. Close ), while human disturbance, e.g. skiing, can be locally important (38 Zeitler, A. (1995). Skilauf und Rauhfusshühner [Skiing and Tetraonids]. Orn. Beob.. 92: 227–230. Close ). Promoting management practices that favour the species often easier in countries where harvesting also important, e.g. Finland (28 Swenson, J.E. and Danielsen, J. (1991). Workshop summary: status and conservation of the Hazel Grouse in Europe. Ornis Scandinavica. 22: 297–298. Close ). Because of species’ enormous range, protected areas play only very limited role in its preservation, although conservations units can be locally important to protect subpopulations, e.g. in Greece, Hungary, Japan, Mongolia and Belgium (26 Storch, I. (2007). Grouse: Status Survey and Conservation Action Plan 27747746–27741774. IUCN, Gland & World Pheasant Association, Fordingbridge. Close ). Reintroduction attempted in some areas, e.g. in W Germany (39 Starling, A.E. (1991). Workshop summary: Captive breeding and release. Ornis Scandinavica. 22(3): 255–257. Close ).