from Sunday Herald, 01 February 2009
Extensive surveys have failed to find any ptarmigan on the island of Arran, indicating that global warming may have restricted their food and prevented breeding. A previous survey recorded 28 birds in 1981.
That suggests that the most southerly mountain where ptarmigan are still breeding is Ben Lomond, north of Glasgow, says the Trust. But if the climate continues changing, the birds could be driven from there in years to come.
Ptarmigan, plump birds which look similar to grouse, are usually only seen on mountainsides and ridges above 700 metres. Their plumage is mottled grey, brown and black in the summer and pure white in the winter to aid camouflage.
To survive, ptarmigan depend on the availability of plants and insects to eat at certain times of the year. Changing weather patterns, combined with pressure from grazing animals, can make it harder for them to find the food they need.
Throughout last year the National Trust for Scotland, with the help of the British Trust for Ornithology, monitored its five mountain properties for ptarmigan. It found over 70 pairs at Mar Lodge in the Cairngorms, 14 pairs at Kintail in the northwest Highlands and eight pairs at Ben Lawers near Loch Tay.
“This is a marked change from 1981, when 28 birds, including chicks, were seen in one season,” said the Trust’s nature adviser, Lindsay Mackinlay. Individual birds may still be present, but it is doubtful that breeding is taking place.
“Ben Lomond and Goatfell are excellent places to see if changing weather patterns will affect the ptarmigan,” he argued. “If predictions about climate change are correct, it is possible that the birds may disappear from Ben Lomond over the coming years.”
The disappearance of the birds on Arran could be part of a natural cycle, or it could be due to the deteriorating health of the mountains and the warming climate, Mackinlay suggested. The precise causes could be complex, and needed further investigation.
He added: “We would ask anyone walking on Arran, Ben Lomond or any of the Trust’s mountains to get in touch with us this year if you do see ptarmigan. Such information is essential if we are to get to grips with what is going on.”
The Royal Society for the Protection of Birds is also worried about the plight of the ptarmigan and other mountain birds. “We're concerned that climate change could affect upland species,” said Jerry Wilson, head of conservation science with RSPB Scotland.