Why do Asian migratory birds stop in Europe?

Migratory birds often confuse the direction, not the distance. The discovery of the group of ornithologists and ecologists at Marburg University - the ornithology association in Bavaria and the Helmholtz Environmental Research Center were published in the Journal of Ornithology .

Scientists have studied thousands of reports of Asian birds from the warbler to the stray birds who have strayed to Europe. They discovered the distance from the breeding area in northern Siberia and the winter holiday area in South Asia close to the distance from the breeding area in Europe. The closer the distance is, the greater the number of a particular species, the higher the probability that the birds will go to Europe.

The body size of birds is not the cause. It has long been suspected that ' stray people ' have been blown off by the weather. However, the new finding demonstrates the hypothesis that stray birds have mistaken the wintering area because of their migration program . Because there are still many questions that have not been answered regarding the spread of H5N1 bird flu, scientists are very interested in studying migratory birds. However, they believe that the virus does not spread through migratory birds but spread through international trade in poultry products. Either way, the risk of wandering birds is the lowest.

The new finding explains why stray birds in central Europe are migratory birds far away from eastern Asia.The programmed trip in the genes of short-distance migratory birds from Asia will end only somewhere in northeast Asia.(Photo: Deutsches Zentrum fur Luft- und Raumfahrt (DLR) / modified from Susan Walter / UFZ)

During the study of these birds in Europe, scientists measured their body mass, wing length, breeding area, distance from the breeding area to winter break as well as distance from the breeding area to the central Europe of 30 migratory birds. Their source of information is the information in the book Handbuch der Vogel Mitteleuropas (handbook of birds in Central Europe) conducted in the early 1990s.

8 species of warblers and 6 species of the sparrow family must pay attention to scientists. A particularly observed species is the golden forehead warbler ( Phylloscopus inornatus ) observed thousands of times by voluntary ornithologists in central Europe between 1836 and 1991. This breed breeds in the Siberian taiga. south of the Arctic belt and spent the winter in the subtropical and tropical areas of southeast Asia. Other Asian warbler species are observed less frequently in central Europe.

In contrast, 5 species of thrush appear nearly 100 times. If stray birds are guided by the weather, smaller birds will be swept up more often than large birds. However, the researchers found no relationship between the frequency of stray birds with its body size even when using statistical analysis. Besides, the golden forehead warbler appeared in central Europe so often that it was impossible to rely on unusual weather conditions during the migration process to explain.

The species that tend to concentrate most in Europe are the most common species in Asia and also popular relatives in Europe ( chiffchaff warbler ) and central Europe ( European willow warbler ). Dr. Jutta Stadler of the Helmholtz Environmental Research Center in Halle / Saale explains: ' The more species there is, the more likely it is that the individual in the herd' fails the program ' . They fly in the same distance but in the opposite direction and so they came to Europe. That's why we have a large number of Asian birds straying here. '

Scientists believe that the cause is due to errors in the genetic migration program. The direction of flight as well as flight time is passed down from generation to generation. That means migration is the result of genetic programs, through which birds have adapted to adapt to climatic conditions.

However, migratory birds can adapt to changes in environmental conditions in just a few generations. Their genes are responsible for the restlessness of the distance that most of them pass thousands of kilometers to the winter break. But people have long wondered why the individual birds of a certain species go on straying constantly.

Golden forehead warbler - Phylloscopus inornatus (Photo: hi.is)

Robert Pfeifer, secretary-general of the Bavarian Ornithology Association, said: 'In these cases, a simple genetic program made birds turn right instead of turning left. We can compare these stray birds with road drivers. They flew against the intercontinental migration route '.

"It can be acknowledged that for most migratory birds it is a one-way trip. Although there are signs that some individuals also" want "to have a winter vacation in the southern region. Europe, and none of them returned to Asia, the birds had a partner who didn't come back, so we couldn't know what happened to them. ' The new findings explain. Why would the stray birds in central Europe be migratory birds far from eastern Asia? The programmed trip in the genes of short-distance migratory birds from Asia will only end. somewhere in northeast Asia.