文档介绍：智课网 TOEFL 备考资料候鸟被迫迁徙更远一托福阅读机经背景 Climate change will force bone-wearybirds migrating to Europe from Africa to log extra mileage, with possibly devastating consequences, according to astudy released on Wednesday. The annual voyage of some species, which fly north in search of food and suitable climes, could increase by as much as 400 kilometres (250 miles), the research found. "Marathon migrations for some birds are set to e even longer," said Stephen Willis, a professor at Durham University in Britain and the main architect of the study. "This is bad news for birds like the Whitethroat, mon farmland bird. The added distance isa considerable threat. "As temperatures rise and habitats change, birds will face their biggest challenge since the Pleistocene era, which ended 11,000 years ago ”, he said ina statement. Some 500 million birds migrate each year from Africa, some weighing as little as nine grammes (three-tenths of an ounce). plete a voyage that can be thousands of kilometres long, birds have to fatten themselves up to twice their normal weight. Some even shrink their ans to e more fuel efficient, so any additional distance travelled takes its toll. The study is published in the Journal of Biogeography. From 2071 to 2100, nine out of 17 species examined are projected to face longer migrations, particularly birds that cross the Sahara desert, the study found. Some birds trave