Migrating birds filled the pale sky.

迁徙的鸟布满了灰白的天空。

《柯林斯英汉双解大词典》

Migrating birds affect ecosystems both at home and at their winter destinations, and disrupting the traditional routes could have unexpected side effects.

候鸟会影响老家和冬季目的地两者的生态系统，而扰乱传统路线可能会产生意想不到的副作用。

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To test the idea, caged night-migrating birds were placed on the floor of a planetarium during their migratory period.

为了验证这个想法，这些在夜晚迁徙的候鸟被关进笼子里，并且在它们的迁徙期间被放置在一个天文馆的地面上。

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It is now a wildlife reserve and a nationally important haven for migrating birds.

BBC: Spurn Point 'not disappearing'

There is also great concern that flu might be carried to poor African nations by migrating birds.

ECONOMIST: Calls for more money as the threat looms ever larger | The

Birdwatchers, for instance, can see some 140 species of migrating birds pass over Egypt's deserts, twice a year.

ECONOMIST: For a tourist, Egypt can be either