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You Call It Music, They Call It an Air Raid Songs can ha

游客2023-12-11  9
问题                     You Call It Music, They Call It an Air Raid
    Songs can have a powerful effect on people. Play " Gypsies, Tramps and Thieves" to many baby boomers, for example, and chances are they’ll run off, hands over their ears. Songs can have a powerful effect among birds, too. Consider the black-capped chickadee. When it sings its " chick-a-dee" song, its flock mates come running. The song is a warning that a hawk, owl or other predator is moving nearby, and the other chickadees arrive to harass the enemy until it leaves.
    Researchers from the University of Montana have discovered that this warning call is a coded signal. By varying the call, a bird communicates to other birds the size of the predator, and thus the scope of the danger. " This is so far the most finely detailed alarm call system that we’ve found," said the lead researcher, Christopher N. Templeton, who is now a doctoral student at the University of Washington. The findings appear in the current issue of the journal Science.
    Mr.Templeton and his colleagues exposed chickadees to 15 different species of predators and recorded and analyzed the calls the birds made. In addition to "chick-a-dee", the birds make a high-pitched "sect" call when they spy a predator flying in the air. Upon hearing this call, the other birds either dive for cover or remain motionless so as not to be spotted. But it’s the "chick-a-dee" call that the researchers focused on. "They change a number of different features about these calls," Mr. Templeton said. "But most are not audible to us except the number of dees’ at the end."
They found that the birds varied the number of "dee" sounds depending on the size of the predator. More "dees"—as many as 21 in one case—were sounded for smaller predators like the Northern pygmy owl. Because chickadees are small and fast, smaller, more quick-moving predators are more of a threat than larger ones.
    The more "dees", the more chickadees show up to harass the predator, by dive-bombing it or making noises in its face. "The goal is to drive it out of their territory so that it is no longer a threat," Mr. Templeton said. This "mobbing" response to the calls is probably learned behavior, he said, a way that birds teach their young about risks. "It’s a means by which adults tell the kids in the flock, ’ These guys are dangerous,’" Mr. Templeton said. [br] It can be inferred from the article that "Gypsies, Tramps and Thieves" is______.
选项 A、Gypsie’s song
B、an alarm call to hint at danger
C、a bad song referring to crimes
D、a warning that the police is nearby
答案 C
解析 本题考查推理引申。第一段开始部分讲述歌曲对人的影响只是一个引子，目的是引出后面部分的内容，即呜叫对鸟儿的影响。呜叫对鸟是警报，但对人并不是。因此首先排除[B]和[D]项。然后从关于人们对这首歌曲的反应的描述(捂着耳朵跑开)可知，这首歌曲让他们反感，所以[C]项正确。
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