The black grouse (Tetrao tetrix) has experienced a serious decline over the last century. Restoring a healthy mosaic of habitats is crucial for the recovery of this attractive bird.
Global distribution
The black grouse is found throughout northern Eurasia, with a continuous distribution from Great Britain to south-eastern Siberia. The most southerly populations are found in Kyrgyzstan and North Korea, with the northern extent of its range being northern Norway. In western and central Europe its population is highly fragmented: populations are very small and isolated in a number of countries and it no longer breeds in Denmark. Its overall population has declined, particularly in Europe, although its population is more stable in its Russian stronghold. Black grouse usually require a mosaic of habitats, ideally including heath and bog along with open woodland and scrub for cover. There are thought to be seven or eight subspecies of black grouse, the only geographically isolated one being the most westerly of all, Britain’s Tetrao tetrix britannicus.
Distribution in Scotland
This grouse was once distributed through most of Great Britain. However, its numbers have declined drastically over the last century, and its range has retreated rapidly northwards. A 2005 survey coordinated by the Royal Society for the Protection of Birds reported an alarming 22% decline in the preceding ten years. Its core population is now in Scotland, where there are an estimated 3,344 of the UK’s 5,078 displaying males. There are smaller populations 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 the 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. Drainage of bogs (which are important foraging grounds for chicks) has also contributed to the decline, while commercial afforestation has shaded out important berry plants such as blaeberry (Vaccinium myrtillus). High tensile deer fences pose a serious hazard to black grouse: when alarmed, these birds tend to fly fairly low, and seek refuge in nearby trees. They often do not see fences in time and are killed as they hit them. Furthermore, illegal shooting during the breeding season can affect both population and breeding success. Climate further complicates the picture, as cold, wet weather in June and July has increased mortality among newly-hatched chicks, which are unable to regulate their own body temperature and are therefore vulnerable to poor weather.
A number of measures are being used to increase the black grouse population, including restoration of preferred habitats, as well as predator control. Redundant fences are being removed, while those essential for woodland regeneration are marked in various ways to make them more visible, and are strategically positioned so as to pose less of a hazard. Otherwise, alternative methods such as deer culling are preferred ways of encouraging regeneration. Mature, open pine and birch woodland, bogs and heath were once much more widespread in Scotland, and restoration of these habitats is playing a key role in black grouse recovery.
