The Lac du Der was once just a passing glimpse for hundreds of thousands of cranes flying from Scandinavia in search of sunshine, but with global warming the French reservoir has become an attractive winter retreat. The Lac du Der was once just a passing glimpse for hundreds of thousands of cranes flying from Scandinavia in search of sunshine, but with global warming the French reservoir has become an attractive winter retreat. Ecology Phys.org – latest science and technology news stories