The results of genetic studies on migratory birds substantiate the theory that in the case of a continued global warming, and within only a few generations, migratory birds will subject to strong selection and microevolution - at first begin to fly shorter distances and at a later stage, stop migrating, and will thus become so-called "residents". In a selection experiment with blackcaps from southwest Germany, Francisco Pulido and Peter Berthold at the Max Planck Institute for Ornithology in Radolfzell were able to show that first non-migratory birds are to be found in a completely migratory bird population after only two generations of directional selection for lower migratory activity. The strong evolutionary reduction in migration distance found in this study is in line with the expected adaptive changes in bird migration in response to environmental alterations caused by climatic change. (The Proceedings of the National Academy of Sciences, PNAS, April 5, 2010)
For generations, humans have been watching flocks of migrating birds flying to their winter quarters in the autumn, and awaiting their loud songs announcing their happy return in the spring. The timing of their migration is adjusted to the availability of resources, such as food and habitats, in the stopover areas as well as in the non-breeding and breeding areas. For migratory birds it is essential to be in the right place at the right time.
For some years, it has been possible to demonstrate using data collected in the wild that some species of migratory birds respond to the increase in temperature and to the subsequent changes in the environment. The blackcap is one of the species where changes in migratory behaviour have been most consistent. Today, blackcaps return to their breeding sites earlier, lay their eggs earlier, and leave us later in the autumn. One population even established a new wintering area in the British Isles, instead of flying all the way to Spai
|Contact: Leonore Apitz|