What happens to birds which spend the spring and the summer in Europe and Asia but disappear in the autumn? Where do they stay in the wintertime? It is not a secret, we know that birds migrate. This was not always so. In the old times, people spent their entire lives in one place and they knew very little about what was outside their immediate surroundings. If they’d heard about foreign lands, they could hardly imagine what they looked like. Therefore, their explanations of seasonal disappearance of birds tended to be rather fantastic. For instance, they believed that barn swallows, whose large flocks they could observe in reedbeds in the autumn, spent winters at the bottom of lakes. When the birds disappeared (or set out on the journey to Africa – as we now know), people thought that they had dived in and fell asleep underwater, hooked together by legs. Some fishermen even reported fishing out fragments of “swallow chains” and they were taken seriously. One of the characters in a play written by Polish poet Juliusz Słowacki in 1835, Lake Queen Goplana wakes up in early spring from her winter sleep and emerges from the waters with a wreath of sleeping barn swallows on her head. Her coming is announced by those birds that are already awake; they strike the little wings against the surface of the lake from below. In the spring, the first swallows were usually observed flying very low above the water as they caught insects, drank or bathed. It seemed obvious that they had just woken up and come up from the bottom. Many methods of tracing birds’ trips have been developed since then. We know much more about the world; we can visit faraway countries and see birds in their winter habitats.