Cliffs, screes and rocks are rocky, rupestrine environments. Their long exposure to shade or sun, and the lack of soil mean that the plant species living there must constantly adapt. Storing water in thick leaves, hairiness, leaf folds to avoid perspiration and dwarfism are all features that plants have developed to survive in this mineral environment. Some birds have become specialists in nesting in cliffsides, such as the peregrine falcon, the alpine swift and its 60-cm wingspan or the Eurasian crag martin. Uninterested in these open environments, the rare short-toed snake eagle, which eats snakes, the Eurasian eagle-owl or the red kite prefer to nest in the large trees below.