单选题
If your mother wants to tell you something, she uses
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. Birds can not
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as we do. But some birds can make sounds to
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their young of danger. They have their own
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to make the young birds do
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things.
The jackdaw(寒鸦)is a kind of blackbird that
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in Europe. Jackdaws live together
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flocks (群). Young jackdaws do not know their
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When an older jackdaw
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a dog, it makes a
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rattling (咯咯响的)sound. The younger birds know this sound means an enemy is
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. The sound warns them and
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them to know their enemies.
If a young jackdaw is in a
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place, a jackdaw parent flies
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him from behind. The parent bird flies low over the young birds back. The parents tail feathers move quickly from side
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side. It is trying to say,"
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me."
At the same time, the parent calls
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, "Key-aw, key-aw." The parents means, "Fly
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with me." The young bird then follows the older one home.
Young jackdaws do not have to learn
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certain sounds mean. They know the
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of these sounds from the time they hatch.