无需人工帮助的物种迁徙也只能维持几个月的时间。
There are a few quarters left for species to migrate through without help.
在克雷默早期的研究中，他发现被关在笼中的候鸟在它们通常开始在迁徙的大致时间会变得非常不安。
Early in his research, Kramer found that caged migratory birds became very restless at about the time they would normally have begun migration in the wild.
我们需要智慧和决心，以确保迁徙的物种能够在更长时间里继续它们的旅程。
We will require wisdom and resoluteness to ensure that migrating species can continue their journeying a while longer.
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