Black Grouse:Black Grouse 14/8/07 14:56 Page 1 Black Grouse (Tetrao tetrix) The black grouse has experienced a serious decline over the last century. Restoring a healthy mosaic of habitats is crucial for the recovery of this attractive bird. Worldwide distribution The black grouse is found throughout northern Eurasia from Drainage of bogs (which are important foraging grounds for Great Britain to south-eastern Siberia. The most southerly chicks) has contributed to the decline, while commercial populations are found in Kyrgyzstan and North Korea, with the afforestation has shaded out important berry plants such as northern extent of its range being northern Norway. In western blaeberry (Vaccinium myrtillus) . High tensile deer fences pose and central Europe its population is highly fragmented: a serious hazard to black grouse: when alarmed, these birds populations are very small and isolated in a number of tend to fly fairly low, and seek refuge in nearby trees. They countries and it no longer breeds in Denmark. Its overall often do not see fences in time and are killed as they hit them. population has declined, particularly in Europe, although its Furthermore, illegal shooting during the breeding season can population is more stable in its Russian stronghold. Black affect both population and breeding success. Climate further grouse usually require a mosaic of habitats, ideally including complicates the picture, as cold, wet weather in June and July heath and bog along with open woodland and scrub for cover. has increased mortality among newly-hatched chicks, which There are thought to be seven or eight subspecies of black are unable to regulate their own body temperature and are grouse, the only geographically isolated one being the most therefore vulnerable to poor weather. westerly of all, Britain’s Tetrao tetrix britannicus. A number of measures are being used to increase the black Distribution in Scotland grouse population, including restoration of suitable habitats, as well as predator control. Redundant fences are being removed, This grouse was once distributed through most of Great while those essential for woodland regeneration are marked in Britain. However, its numbers have declined drastically over various ways to make them more visible, and are strategically the last century, and its range has retreated rapidly northwards. positioned so as to pose less of a hazard. Otherwise, alternative A 2005 survey coordinated by the Royal Society for the methods such as deer culling are preferred ways of encouraging Protection of Birds reported an alarming 22% decline in the regeneration. Mature, open pine and birch woodland, bogs and preceding ten years. Its core population is now in Scotland, heath were once much more widespread in Scotland, and where there are an estimated 3,344 of the UK’s 5,078 restoration of these habitats is playing a key role in black displaying males. There are smaller populations grouse recovery. in northern England and Wales, although the decline has actually been reversed in the latter. The reasons for this decline are varied and complex. Changes in agricultural practices, and in particular an increase in sheep numbers, have led to herb-rich and wet pasture areas becoming overgrazed, with a resulting decline in the insects essential for the survival of young grouse. In addition, overgrazing by sheep and deer has damaged areas of heather moorland, heather (Calluna vulgaris) being an important winter food source for black grouse. Excessive grazing has also suppressed native woodland regeneration, depriving the birds of some valuable food sources as well as refuge from predators. The lyre-shaped tail feather of a male black grouse. Two male black grouse displaying on a lek. Black Grouse:Black Grouse 14/8/07 14:56 Page 2 Conservation status Locally extinct in many regions, the black grouse is the fastest Blackcocks participate in a fascinating territorial and declining bird in the UK and is on the Red List of Birds of breeding display known as a lek (from the Swedish leka – Conservation Concern. It is protected under the Game Acts play). They gather on an open area of ground where they strut, (closed season 11 December-19 August); while it may be fanning out their tails, spreading their wings slightly and legally hunted in the open season, many estates choose not to inflating the wattles above their eyes. The dominant males gain do so. It is classed as Vulnerable in Europe, and is in Annex the favoured position at the centre of the lek, increasing their II/2 of the EC Birds Directive and Appendix III of the Bern chances of mating. The females, who only attend in late March Convention. However, its global population is not thought to to mid-May, are positioned around the edge of the lek, be endangered, and it is classified as being of Least Concern. watching and selecting the most impressive males to mate with. Lekking takes place almost year-round, except for July and August when the males moult. Outside of the breeding season they lek to establish hierarchy and defend territories. From late April to early June, greyhens typically lay a brood of 6-10 eggs, which are buff with brown spots. They are normally laid in a simple hollow in the ground, with little lining, although they are usually concealed by surrounding tall vegetation such as heather or rushes (Juncus spp.) . The eggs are incubated for about 24 days; the chicks hatch in mid to late June and fledge after about four weeks. Black grouse do not form pair bonds, and the male plays no part in rearing the chicks. The average lifespan of a black grouse is around five years. Ecological relationships of black grouse As with other herbivorous animals, the black grouse plays a role in keeping the vegetation structure in an area more varied A female black grouse - her subdued plumage provides good camouflage. than if it were completely ungrazed. During their insectivorous Physical characteristics and behaviour phase as fledglings they also help to regulate numbers of the caterpillars and other invertebrates they eat. The black grouse (also known as ‘blackgame’) is a member of The black grouse is prey for numerous predators, including the grouse family Tetraonidae . Roughly the size of a domestic raptors such as golden eagles (Aquila chrysaetos) and hen hen, the male, or ‘blackcock’, is 49-58 cm. in length with a tail harriers (Circus cyaneus) . Pine martens (Martes martes) , foxes measuring around 15cm.; he weighs approximately 1.25 kg. (Vulpes vulpes) , crows (Corvus corone) and stoats (Mustela The female or ‘greyhen’ is slightly smaller at 40-45 cm., and erminea) eat the birds as well as their eggs. weighs 950 g. The male has black plumage with a bluish sheen. Black grouse are host to a variety of parasites. These He has white wing-bars, which are only visible in include feather mites, for example Tetraolichus gaudi , flight, white under-tail coverts, and a distinctive tapeworms such as Hymenolepis spp. , and blood parasites such lyre-shaped tail. The female has grey-brown as the protozoan Leucocytozoon lovati . On an evolutionary plumage, (providing excellent camouflage when timescale, these parasites can improve the health and vigour nesting on the ground) with pale wing bars, and of the species overall, by selecting out weaker individuals. her tail has a slight notch at the end. Both sexes The black grouse depends on other animals to provide have a red patch called a ‘wattle’ above each eye. some of the habitat it requires. In some areas Among its calls are a rapid cackling and a harsh conservationists use cattle to maintain the open hissing sound. When displaying, the males habitats the grouse need for their leks. It is produce a pigeon-like, bubbling call, interspersed likely that in former times, herbivores such with a ‘sneezing’ noise. as the extinct wild cattle, or auroch (Bos The diet varies considerably through the primigenius) would have played a role year, and also in different parts of the bird’s in keeping patches of the forest range. Birch buds (Betula spp.) along with relatively open. heather and blaeberry shoots are important Human management for the winter food sources. Cotton grass black grouse also has a knock- (Eriophorum spp.) and larch buds (Larix on effect for other wildlife. As spp.) are eaten in spring, pine pollen this bird requires a variety of (Pinus sylvestris) in early summer, blaeberries in habitats, management for the late summer, and rowan berries (Sorbus aucuparia) in autumn recovery of black grouse benefits a wide range of other and winter. For the first three weeks of their lives, chicks feed species. Conservationists are working hard to aid the recovery on protein-rich invertebrates, particularly moth caterpillars and of this attractive bird, and there is still hope that the overall sawfly larvae (suborder: Symphyta). downward trend can be reversed. © 2007 Trees for Life, The Park, Findhorn Bay, Forres IV36 3TZ, Scotland. • Tel. 0845 458 3505 • Fax 0845 458 3506 E-mail: [email protected] • Web site: www.treesforlife.org.uk • Scottish Charity number SCO21303 Text by Dan Puplett. Photographs by Laurie Campbell. Illustrations by Caragh McAuley. References for this Species Profile are available on our website, or by request. 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