See map at right: Green represents autumn/southward migration; red denotes winter range; and yellow represents spring/northward journey.

图：绿色线路为秋季燕鸥南迁路线；红色线路为其冬季飞行路线；黄色线路为春季燕鸥北飞路线。

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The researchers compared the resulting population migration to the mass movement of African Americans northward at the end of the Civil War.

研究者们比较随之而来的人口迁移与内战结束后非裔美国人向北大规模移动。

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We saw and heard about the impacts, from slumping land due to the melting of permafrost to hunter stories about the northward migration of species and the challenge that early ice break up poses for transportation.

CNN: Sailing the Northwest Passage: mission accomplished