Japan organized a nationwide research team to study the migration routes of small migratory birds that come from Siberia or other parts of the continent such as Dusky Thrush and Rustic Bunting. However, the Far East Region, which is thought to be the breeding site and travel route of migratory birds, does not have any records on the migration routes of small migratory birds that travel between Japan and the continent. Thus, a joint study was launched to understand the travel routes, lifespan, breeding season, and age of migratory birds in Russia.