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

Causes of decline

Weather

The weather can have a substantial effect on breeding success, with young chicks particularly susceptible to cold, wet weather during mid June to mid July (the first few weeks after they hatch). Rainfall in June, along with predation by crows and the interaction of the two, reduced breeding success during a study at Abernethy Forest, Strathspey. Studies in Belgium found similar trends, including negative effects of wetter June weather and milder winters (Loneux et al. 1997). Capercaillie, a similar large grouse species in serious decline, have had poor breeding success over the last 25 years, linked to the delayed warming of temperatures in April. (Moss et al. 2000).

Climate Change

Changes in weather patterns may be linked to changes in global climate. Some changes to wildlife have already been noted, such as the northern extension in range of some butterflies. Recent climate change scenarios (UK Climate Change Impacts Programme) suggest that in the uplands, both summer and winter temperatures will increase, as will winter rainfall, but snow will be less frequent, and there will be less rainfall in the summer. Some of these changes (such as warmer, drier summers) may benefit black grouse productivity, but these may be outweighed by bigger changes to black grouse habitats and the timing/extent of insect emergence (chicks' food supply). Modelling suggests that the UK 'climate envelope' for black grouse (its potential range) will reduce to about one-fifth of its current range by 2080. However, climate change predictions involve many assumptions and must be treated cautiously.

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Cotton grass is an important host plant for insects on which black grouse chicks depend. Climate change may reduce the abundance of plants such as these. Andy Hay, RSPB Images

One example of possible climate change in the uplands is that average soil moisture is predicted to decrease across the UK. As a result, some key plants found in upland hay meadows, native pinewoods and blanket bog habitats – such as cotton grass Eriophorum vaginatum, which is a good source of food for black grouse chicks – will lose 'climate space'. They will be unable to survive in the drier conditions and will only be found farther north and at higher altitudes.

What can be done?
The weather is, of course, beyond anyone's control, but by providing the best possible conditions for black grouse, we may be able to overcome the worst extremes of the weather. Experts predict that some changes in climate are now inevitable, but by managing our use of carbon fuels, we can all do something to limit the worst extremes.

Other factors in the decline
Agriculture
Deer
Fencing
Forestry
Predation
Shooting