Majority of the bird species in North Europe are migratory spending part of their life cycle outside breeding areas. Because of this their population dynamics for instance can be affected by environmental changes during the both winter and summer areas. Long-term bird ringing has revealed migration routes of species and current modern tracking devices enables to investigate migration online in the globe (see for examples from our Habitrack -consortium project). Annual migration numbers and phenology of birds are also affected by environmental changes. In our research, we are for instance combining migration data with the species distribution data to improve our understanding about overall changes in the bird populations. In addition, we are studying processes of bird migration. The key source of the bird migration data is the Hanko Bird Observatory, which is maintained by the Ornithological Society of Helsinki region, Tringa.