Winter sports fans threaten alpine fauna

Black grouse are particularly sensitive to human activities (Patrick Patthey)

Trendy winter sports in the Alps are threatening the survival of wild animals, according to a study led by scientists from Bern University.

In cooperation with Vienna University and the Swiss Ornithological Institute, the researchers say that off-piste skiers, free-ride snowboarders, people who go on ski tours and those on snowshoes are the culprits.

The study, released on Wednesday, is the first to quantify the physiological effects of winter sports on wild animals. The results show that sensitive birds are suffering dangerous amounts of stress.

The findings were published in the British research journal “Proceedings of the Royal Society B: Biological Sciences.”

The study says that in the long term only the installation of winter protection areas can help the animals counter the increasing pressure of human activity on their ecosystems.

Black grouse

The researchers, led by Raphaël Arlettaz of Bern University, studied the behaviour of the black grouse, which lives in areas most popular with skiers, the zone between forest and high-altitude grassland.

The scientists measured the birds’ stress levels by determining the amount of corticosterone found in the animals’ faeces. This hormone is an indicator of stress responses.

Under normal circumstances, the grouse spend 20 hours per day in winter resting in a sort of igloo, saving their energy and avoiding predators. The researchers collected the faeces in these igloos.

The results showed that in areas where there is no or little human presence, the animals suffered no stress. But in areas where people go ski touring or snowshoeing or close to resorts, levels of the stress hormone were 20 per cent higher.

The researchers say that even a moderate human presence can have an impact on the animals’ health.

Fear of humans

A second set of results showed that levels of corticosterone jumped by 60 per cent between days when there was no human presence and when one of the scientists visited an igloo. The birds would systematically flee as soon as they noticed someone approaching.

Further research is now underway to determine the impact of human activities on the animals’ well being and their chances of survival.

But the initial results seem to show that exposure to low temperatures and predators outside the igloos could explain why there are 30 to 50 per cent fewer grouse in areas where winter sports are widespread.

The researchers at Bern University are now working on models that will allow them to determine which zones should be set aside for mountain fauna, including the grouse.

swissinfo with agencies

Sensitive animal

The black grouse is a shy bird with a fan-like tail. It is found in Switzerland around the top of the tree line.

In winter, black grouse make themselves a lair by hollowing out the snow and then blocking the entrance with the snow they have scratched up.

The principle is like the igloo, as snow is a good insulator: where the outside temperature may fall as low as -25 degrees celsius, the temperature in the hole will be only around freezing point, and is further warmed by the bird’s body.

They only emerge to find food.

The grouse also have feathers in places where most birds do not: over their nostrils, which slightly warms the air they breathe in, and over their toes, which gives their feet a broader surface area and stops them sinking into the snow. They also have an insulating layer of down, which works by trapping the air.

Despite their adaptations, the number of black grouse is falling.