CoachTo migrate is to travel, each year, from one region to another as the seasons change — leaving before winter for warmer lands where food remains, and returning in spring. The swallow, the stork and the crane are migrators; some travel thousands of kilometres, and find their way back to the very same nest.
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Example 20.9 (Spring undoes it all)
In March and April the order reverses: insects return, the migrators reappear at their old nests, the hibernators wake thin and ravenous, winter coats are shed. The seasons turn, and the animals’ calendar turns with them — next autumn, the swallows will line up on the wires again.