Osmo Rätti a long research background in northern and arctic ecology. His main research interest in recent years has been different aspects of grouse population ecology. Especially, He has studied the impact of parasites and diseases on population density changes of grouse. Also, he is Vice Director of the Arctic Centre. Focus of Research: Population ecology, Causes of grouse population fluctuations, Sustainable harvesting of grouse populations, Parasite-vector-host interaction (blood parasites, black flies, grouse), Habitat fragmentation and population genetics of grouse, Epidemiology of viruses in birds.