Why do birds fly, but we can't

Why don't migratory birds stay in the south?

In autumn, many migratory birds fly to southern Europe or Africa.The journeys are exhausting and sometimes very dangerous. But why do the animals keep coming back and not staying in the warm?

While resident birds stay in one area all year round, migratory birds commute between their breeding areas in Central Europe and Southern Europe or Africa. Many migratory birds head south between September and November, some species start their migration earlier. The migratory birds come back between March and May.

Why do migratory birds fly south?

The reason for the bird migration is the fluctuating food supply in the breeding areas in the different seasons. Because in summer and spring there is a lot to eat for migratory birds in northern and central Europe, they can feed on insects and seeds. When it is colder and the days get shorter, the food supply is scarcer and the migratory birds start their migrations south.

When the migratory unrest begins in a bird is genetically determined. This means that it is innate whether when and where a bird moves.

Why don't migratory birds stay in the south?

The fact that migratory bird species do not stay in the south all year round is due to the competition in the winter quarters. Because bird species that live there all year round are rivals when it comes to foraging. Migratory birds therefore make their way north again when the food supply there is richer again.

How do migratory birds orient themselves?

Migratory birds use various information on their migrations in order to reach their destination. For orientation:

  • The earth's magnetic field
  • The star Sky
  • The position of the sun

The visual center of the bird's brain is designed in such a way that it can perceive the earth's magnetic field - the animals have a kind of "inner compass". The stars help some species to find the right path at night. For birds that migrate during the day, sunlight helps locate them. Migratory birds often use different information at the same time to calculate routes.

Migratory birds and carrier pigeons reach distant destinations with their good sense of direction, but can sometimes deviate from their route or fly too far.

Which birds are migratory birds?

Not every bird flies south in late autumn. Some species stay here, with other species only part of the population flies south. It is therefore between resident birds, part migrants and migratory birds.

  • Resident birds stay in the same place all year round - even in winter. They include blackbirds, great tits, sparrows and the wren, for example. They have thick plumage and eat through a warming layer of fat during the winter. It is therefore important that these bird species find sufficient food during the cold season.
  • At Partial drawers some animals of a bird species remain in the breeding area during the winter, the other part moves south. This can easily give the impression that the population of this species has decreased significantly. The participants include, for example, the star, the Steglitz, the chaffinch, the blackcap and the goldhammer. In total, around 80 percent of the native bird species are among the participants.
    If the temperatures are particularly mild, more resident birds will survive the winter. The journey to the south costs the animals a lot of energy and is also dangerous because of agriculture and hunting. However, if the winter is particularly severe, the part of the bird species that has flown south will benefit.

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Due to the past, relatively warm winters, an increasing number of the partial migrants often remain in the breeding area.

  • Migratory birds fly to the southern part of the globe between September and November. They include, for example, cranes, white storks, house martins and the nightingale.

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Chaffinch: Some specimens overwinter in Germany. (Source: Volodymyr Kucherenko / Getty Images)

Short, medium and long distance migrants

Ornithologists (ornithologists) differentiate between:

  • Short-haul migrants
  • Middle-distance migrant
  • Long-distance migrant

Short to medium distance migrants are for example robins and chaffinches, which migrate from the north-eastern regions of Europe to central or southern Europe. A third of the migratory birds are short-range migrants.

Typical Middle-distance migrant are cranes that often move across Germany in their typical wedge formation on their way to France, Spain or North Africa. The procession of the powerful-voiced song thrush reaches its peak in October. The bird overwinters in western and southern Europe.

To the Long distance migrants include the cuckoo and the nightingale. Some of them cover more than 10,000 kilometers on their hikes in the warm winter quarters. The same goes for barn swallows, sand martins and fitis, which are drawn to tropical Africa in autumn and winter.

Barn swallow: The small birds are long-distance migrants and migrate to tropical regions of Africa. (Source: CarolinaBirdman / Getty Images)

The prerequisites for a successful flight into the distant winter areas are fat reserves, which the animals feed on during the strenuous journey. Some weak or sick migratory birds perish on the grueling journey.

Flight formations during bird flight

Different migratory birds have different flight formations. Geese and cranes fly in the famous Wedge formation, Ducks travel through the air in a straight line, one behind the other.

Migratory birds: In the wedge formation, the animals can save a lot of energy on their migrations. (Source: Patrick Scheiber / imago images)

Some migratory bird species such as the cuckoo fly alone, others in large flocks. The respective formation is important for the division of strength in the group. Experiments in the wind tunnel have shown that the animals can save up to a fifth of their energy with the special flight methods.


The formations are especially important for long-distance migrants, whose journeys are very strenuous. The animals change their positions in the formation again and again so that each bird can recover on the way. Competitive behavior and hierarchies within the flight group also play a role.