Millions of migratory geese are in their northern breeding grounds .
成千上万迁移的鹅群来到北方生育繁殖。
Can migratory birds carry h5n1 over long distances ?
候鸟会长距离携带h5n1型禽流感病毒吗？
Altering the migratory and reproductive patterns of the world 's wildlife has proved more challenging .
改变世界野生动物迁徙和繁衍模式的工作已经证明更具挑战性。
Little is known about the migratory habits of these huge fish .
对于这些大鱼的洄游习性知之甚少。
For many ordinary citizens , dual passports still seem dodgy : a convenience for the cosmopolitan few or a sop to the menacing many , rather than a natural feature of a migratory world .
