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

Causes of decline

Fences

Deer fences
The increase in deer numbers in Scotland has led many landowners to exclude them from forests, both native woodland and conifer plantations. Although fenced exclosures may provide good brood habitat, collisions with poorly located deer fences (and some stock fences) can cause significant mortality for black grouse. Flying through the forest at first light, it is difficult for black grouse to see these wire fences until it is too late. In a study of 80 kilometres (50 miles) of fencing in native pinewood in the Scottish Highlands, one black grouse 'strike' was recorded every 2.5 km (1.5 miles)of fence each year, and at least one black grouse was killed along every 14.7 km (9 miles) of fence (Baines and Summers 1997).

What can be done?

image
Fences kill many birds each year, especially black grouse (such as this female) and capercaillie. S. Taylor, RSPB Images

Stock fences
Lower in height than deer fences, these are used to exclude sheep from woodlands, moorland or simply neighbouring land. They have been used for many years in the uplands, though this use may have increased in recent years because of agri-environment schemes. Black grouse can fly into stock fences and these collisions are frequently fatal. Although this has not been quantified, it is believed that this can be a serious problem when creating suitable habitats for black grouse where populations are already low.

What can be done?

Overhead power-cables are also potentially lethal obstacles to low-flying black grouse, while elsewhere in Europe, ski-tow and ski-lift cables are known to kill birds (Miquet 1990). However, since there are so few ski resorts in Britain, this is not considered to be a serious problem here.

Other factors in the decline
Agriculture
Deer
Forestry
Predation
Shooting
Weather