候鸟

Do you know about migratory birds? There are migratory birds: summer birds and winter birds. Summer migratory birds are birds that 'come north in spring and go south in autumn' and live in very warm conditions all year round, while winter migratory birds ...... are birds that fly north in spring to live far away and cold, only to return in winter. Although they may each spend half of their lives in the same place - they never get the chance to be together.