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. The favoured method, high-tensile
fences, are effective at protecting the trees and understorey vegetation,
but for black grouse (and capercaillie), the benefits are outweighed by
the number of birds that are killed. 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?
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 new
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
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