The ornithologists from the Lund University revealed in their study that birds have an extremely useful habit, they just fly away from diseases. Study’s results published in Nature prove that frequent travellers deal with fewer pathogens.
The migratory birds that breed in Europe but spend most of the year in pathogen-rich Africa became a subject of the research. Ornithologists noticed that these frequent travellers have to deal with the pathogens present in both Europe and Africa. Why?
Initially, the scientists supposed these migratory species to have the most diverse set of immunity genes of all the species researchers examined. Surprisingly, this was not the case. Birds had similar MHC diversity to that of European species. Being travelled thousands of kilometres twice a year between tropical Africa and European breeding grounds, birds are strengthening their immune system.
As they migrate or colonize new areas, they are exposed to entirely new communities of pathogens like bacteria and viruses. After the research at the Molecular Ecology and Evolution Laboratory, the Lund University team has found out that European and migratory songbirds both came from Africa. And this migration and colonisation of new habitats changed their immune systems in a way that suggests they no longer need to worry about African pathogens.
How European birds came from Africa
There is the question: Did European birds come from Africa, or did African birds come from Europe? The reconstruction the past distributions of over 1,300 African and European songbirds over the last 45 million years fall into two main groups: Species that live all year-round in either Africa or Europe (residents), and species that migrate to breed in Europe and spend their winters in Africa (migrants).
Surprisingly, the resident European songbirds have African ancestors, indicating that colonization occurred ‘out-of-Africa’ and into Europe. Similarly, migratory species also have African ancestry suggesting that migration evolved as African species shifted their breeding ranges into Europe.