Published in support of the UK Biodiversity Action Plan for black grouse

Causes of decline

Changes in farming

The farmed landscape has changed significantly during the last 50 years. Encouraged by government grants and subsidies and aided by improved technology, a series of changes has been pressed upon farmers who make their living in the countryside. This has led to the fragmentation of habitat in the uplands, similar to those that may have caused the loss of black grouse from lowland heathland in southern England.

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Grazing by sheep can influence the abundance of invertebrate food for black grouse chicks
RSPB Images Andy Hay (9001998-00136-009 RSPB Images)

Grazing

Grassland

Grazing animals are an important part of habitat management for black grouse, but an increase in the number of sheep during the 1970s and '80s led to the loss of hay meadows, rough grazing and wet flushes, as pasture was drained, ploughed and re-seeded. While the pasture can support more sheep, there is less long vegetation and fewer damp areas for black grouse broods to feed. Studies show that heavy grazing reduces the abundance of invertebrates on which young black grouse depend, and so fewer chicks survive to their first autumn (Baines 1996). Too little grazing can also be a problem for black grouse, as the vegetation becomes too rank and tussocky. Studies in the North Pennines suggest that reducing grazing for 7-8 years can benefit black grouse, but then its value to black grouse falls (Calladine et al. 2002). Trials are now underway, funded by Defra, to see whether short pulses of heavier grazing (or cutting) provide a structure that black grouse prefer (Warren et al. 2003).

Grazing can also prevent the regeneration of berry-bearing trees, such as rowan and willow, which can be an important food resource during the winter. A lack of nutritious food may lead black grouse to extend the area over which they feed, so increasing the risk of predation as birds travel further in search of food.

Moorland

Black grouse feed on heather during the winter months (October to March). Heather moorland has been degraded and lost due to overgrazing by sheep (and deer). High grazing pressure by sheep and deer is particularly damaging during the winter months when heather is favoured due to its higher nutritional value than grass as it is outside the grass growing season. This has reduced the quality and proximity of feeding areas for black grouse.

What can be done?

Arable

Until the 1970s, many upland farms had small-scale, rotation systems of root crops, oats and grass. Increased specialisation means that this has almost gone, with most upland farms concentrating solely on livestock. Black grouse were seen regularly feeding on arable crops, especially on spilt grain, stooks, stubbles and root crops during the autumn and winter. The importance of these arable crops to the survival of adult or first-year birds (and therefore to the population) is not known, but it has been suggested that it could benefit the birds.

What can be done?

Other factors in the decline
Deer
Fencing
Forestry
Predation
Shooting
Weather