White Storks migrate to the south for the winter – they need to do it to make sure that they can find enough food, it is not easy to find food in the northern parts of Europe in winter. Some of them spend their winter in the south of Spain, and some of them go further south to the central Africa. They can travel up to 12,000 km!
Storks travel only by day, and to travel long distances they must use a soaring flight on hot currents of air called thermals. Thermals are invisible – they are only a hot air. Entering a thermal, a Stork is pushed high by the rising air. When the stork leave the thermal at its top, it can gently glide downwards over long distances.
It is much easier for birds to travel in larger flocks. When one bird finds a thermal all others follows it and start soaring. The more that birds travel together, the easier for them is to find a good thermal – that is why bigger flocks travel faster than single birds. In autumn, you can see flocks of up to 10,000 birds at a time.