Clack, clack, clack. If you hear that sound high up on a bell tower, it is a stork greeting its mate. Storks have almost no voice: they communicate by clattering their bills, known as bill-clattering. The white stork is a very familiar neighbor: Spain has one of the largest populations in Europe. It builds enormous nests that it reuses year after year, and although it used to spend the winter in Africa, many now stay here all year round. Its cousin, the Abdim’s stork, is the smallest of them all. It lives in Africa and travels following the rains, which is why in many places it announces the arrival of the wet season. And it is a farmer’s best friend: it eats grasshoppers and locusts. Two great travelers that soar on warm air, barely flapping their wings.