Where Do Storks Migrate? Routes to Africa and Back

Where white storks spend the winter

The white stork breeds from Portugal and Spain across Europe to western Russia and Turkey. Almost all of these birds leave their nests after the breeding season. Their winter homes depend on which route they take:

• Western storks (from Iberia, France, Switzerland, western Germany and the Netherlands) mostly winter in the Sahel of West Africa, the dry grasslands south of the Sahara, in countries such as Senegal, Mali, Niger, Nigeria and Chad.
• Eastern storks (from eastern Germany, Poland, the Baltic states, Ukraine, the Balkans and Turkey) travel much farther, wintering in Sudan, East Africa and as far south as South Africa.
• Asian storks of central Asia winter mainly from Iran to India.

In Africa, white storks gather in big flocks on savannas and farmland, often following swarms of locusts and grasshoppers or feeding near grass fires that flush out insects.

The two great routes: Gibraltar and the Bosphorus

White storks are soaring birds. Instead of flapping all the way, they climb in thermals, columns of rising warm air, often to about 1,200–1,500 m (3,900–4,900 ft), then glide to the next thermal. Flapping flight burns far more fat than soaring, by one estimate about 23 times more per kilometer.

Thermals form over sun-warmed land but barely at all over the sea, so storks avoid the open Mediterranean. Instead they use two land bridges:

1. The western route goes through France and Spain to the Strait of Gibraltar, where Europe and Africa are only about 14 km (9 mi) apart. The storks then cross Morocco and the Sahara to West Africa.
2. The eastern route goes through the Balkans to the Bosphorus at Istanbul, across Turkey, and down through the Levant (Syria, Lebanon, Israel) and Sinai. Storks then follow the Nile valley south into East Africa.

The eastern route is far busier. Roughly half a million white storks pass over Israel each year, making it one of the great bird migration spectacles of the world. Storks there travel with eagles, buzzards and pelicans, and flocks can stretch across the sky.

Across Europe there is a “migratory divide”, a line running roughly through the Netherlands and Germany. Storks hatched west of it usually head southwest toward Gibraltar, while those hatched east of it head southeast toward the Bosphorus.

Timing and distances

Most white storks leave Europe in August and September. Young birds often set off first, before the adults. The autumn journey to Africa takes on average about a month, while the spring return is slower, taking about seven weeks, because birds wait for good weather and stop to feed.

Storks begin returning in late winter. They pass through Sudan and Egypt from about February to April and reach their nests mainly from late February to April, with the earliest birds arriving in western Europe.

Distances vary enormously. A stork from Poland wintering in South Africa may cover roughly 10,000 km (6,200 mi) each way, one of the longer journeys of any large land bird. For comparison, a stork from Spain may only cross the strait to Morocco, or not migrate at all. For other remarkable journeys, see the longest animal migrations.

Young storks follow an inherited direction on their first trip. If strong winds blow them off course, they cannot correct for it and may end up in a new wintering area. Adults, which know the way, can compensate. Scientists are still studying exactly how birds find their way, as described in How do birds know where to migrate?

The arrow stork that proved migration

Until the 19th century, many Europeans did not know where storks and other birds went in winter. Some thought they hibernated, turned into other animals, or even slept at the bottom of ponds.

The answer arrived in 1822, when a white stork was found near the village of Klütz in northern Germany with an African spear about 75 cm (30 in) long stuck through its neck. The bird had survived the wound and flown all the way back to Europe. The preserved specimen, known as the Pfeilstorch (“arrow stork”), is still kept at the University of Rostock. It was striking evidence that storks really did winter in Africa. About two dozen similar arrow storks have since been recorded in Germany.

Scientific study began in 1906, when German ornithologist Johannes Thienemann started ringing birds at the Rossitten bird observatory on the Baltic coast. By the Second World War, about 100,000 storks, mostly young birds, had been fitted with numbered rings, and recoveries in Africa mapped the two routes in detail.

What satellite tracking has revealed

Today, white storks are among the best-tracked birds on Earth. Since the 1990s, scientists have fitted storks with satellite and GPS transmitters weighing only a few dozen grams. Tracking has shown:

• How storks use thermals and wind, flying faster over deserts where food and water are scarce.
• That young storks have a much higher risk of dying than adults, especially on their first migration.
• That many deaths are caused by people, through collisions with power lines, electrocution and hunting along the routes.

Some tagged storks can be followed online by the public, and their journeys are tracked by schools across Europe.

Why more storks are staying in Spain

One of the biggest changes in recent decades is that many white storks no longer go to Africa. Since the 1980s, tens of thousands of storks from Spain and Portugal, along with some from central Europe, have started spending the winter in Iberia.

The main reason is food. Large open landfill sites provide food all year, and rice fields in southern Spain are full of introduced red swamp crayfish. Milder winters also help. Tracking shows that storks that winter close to these food sources save the energy and danger of a long journey. As EU rules close open landfills, scientists are watching to see whether some of these birds start migrating again.

To find out why the birds also choose to nest on rooftops, read Why do storks nest on roofs?