Labels:animal | bird | book | bulletin board | door | earth | fence | person | plaything | rock | sculpture | sky | tree | windowpane OCR: MIGRATION Birds hat is migration? Annually, millions of birds leave their southern wintering grounds in search of pooj and a place raise family Guided by the stars. change in sunlight, and the earth' magnetic field following their ancient instincts migratory birds make this epic northward The Bobolink is one of the journey every year. The biological urge that Which birds make the top migrants. covering 7.000 triggers migration causes birds to store up trip non-stop? miles or more between the fat for the energy to make the trip They migration, clover fields of Canada and battle exhaustion, predators. and storms we During awaker Spring to the sounc the grasslands of Argentina. reach the breeding grounds. Once the voung are fledged the remarkable trip is reversed of the chorus How high do mig ...
