Have you ever heard of vertical migration? When winter arrives in the Alps, many animals (such as birds, mammals and even insects) decend to find protection at lower grounds. After all, a short vertical migration can mean a world of difference in temperature and depth of the snow layer. Even marmots hibernate in a winter borrow that is often two or three hundred meters lower than their summer dwelling. In short: vertical migration is a common phenomenon in our mountains during winter.
Lots of animals decend
When winter arrives in the Alps some birds leave the mountains, looking for warmer and more nutrient-rich places in the south. Rock creepers (Tichodroma muraria) for example like to migrate to Provence, while rock thrushes (Monticola saxatilis) prefer to go further south and fly all the way to Africa. In addition to this well-known migration to the south, the animals that remain in our mountains also migrate: they descend to lower-lying terrain in search for higher temperatures and a thinner snowpack. This is the so-called vertical migration. The list of species descending to seek protection on lower ground is endless: wild boar (Sus scrofa), red foxes (Vulpes vulpes), hares (Lepus europaeus), chamois (Rupicapra rupicapra), alpine marmots (Marmota marmota), red deer (Cervus elaphus), etc…
However, there is one bird species that stays high up in the alpine, even in the harshest of winters: the Alpine chough. On wintery days you might see flocks circling in the Chamonix valley above villages as low as Argentière (1252 m), but after foraging these birds will always return to their alpine habitat where they have their roosting in crevices on steep cliffs.
All in all, vertical migration is a relatively easy way for animals to avoid some of the extreme wintry conditions. However, winter is and will always remain a test for every animal in the Alps, regardless of their altitude.
To be continued…
This blog is part of a series in which I discuss some of the extraordinary strategies and adaptations of wildlife coping with winter in the Alps: