The Migration of Birds The most obvious feature of birds is that they can fly. / This facility gives them great mobility and

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答案 The Migration of Birds The most obvious feature of birds is that they can fly. / This facility gives them great mobility and control over their movements. / Many species can travel quickly and economically over long distances— / up to thousands of kilometers, / if necessary, crossing seas, deserts or other inhospitable areas. / They also have great orientation and navigational skills, / and are able to remember and re-find remote places they have previously visited. / Birds can thereby occupy widely separated areas at different seasons, / returning repeatedly to the same localities from year to year. / Although migration is evident in other animal groups, / including insects, mammals, and fish, / in none is it as widely and well developed as in birds. / The collective travel routes of birds span almost the entire planet. / As a result of migration, bird distributions are continually changing—/ on regular seasonal patterns, and on local, regional or global scales.

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