2. 考研
  3. A. Land of the kiwi. B. Reasons for concern. C. The introduction of predators. D. Explanation for larger bird populations. E. Pr

A. Land of the kiwi. B. Reasons for concern. C. The introduction of predators. D. Explanation for larger bird populations. E. Pr

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问题 A. Land of the kiwi.
B. Reasons for concern.
C. The introduction of predators.
D. Explanation for larger bird populations.
E. Preventing the kiwi decline.
    Kiwis are flightless birds endemic to New Zealand, and by far the smallest living ratites and lay the largest egg in relation to their body size of any species of bird in the world.
    【R1】______
    The kiwi is synonymous with New Zealand, so much so that Australians endearingly refer to New Zealanders as "kiwi" —people from the Land of the Kiwi. This unique bird, recognizable by its short squat body and elongated beak, is under threat. Its small, clawlike wings render the kiwi flightless; it must of necessity live on the ground. The kiwi is thus easy prey to marauding enemies such as humans and mammals.
    【R2】______
    When the great land mass of the south split 75 million years ago, the kiwi and many other ground-living bird species became separated from predatory mammals within what was later to become know as New Zealand. The birds were able to multiply and flourish because there were very few mammals landlocked within the islands. Kiwis have evolved certain mammalian characteristics over time, living on the ground and free as they were from attack by mammals.
    【R3】______
    However, when the Polynesians arrived about 1,000 years ago bringing with them dogs and rats, the kiwi population and other vulnerable bird species soon suffered a severe reduction in numbers. The coming of the Europeans in the eighteenth century brought even more determined predators, including the cat and, especially, the stoat—a kind of weasel introduced to control rabbits. The stoat is a very vicious and efficient killer of kiwis.
    【R4】______
    There are six types of kiwis, and all six are threatened. Two are "critically endangered" because they have populations of less than 250 mature birds. Two are "endangered" meaning that it is estimated that within three generations their numbers will have declined by 50%. The other two are designated "vulnerable" —one because its habitat is shrinking, the other because it is potentially under threat from stoats and other mammals.
    【R5】______
    100 years ago there were more than 5 million North Island Brown Kiwis. Today, there are probably around 30,000 and the population is decreasing at a rate of 6% a year. Only the Little Spotted Kiwi is increasing because of successful attempts to transfer the creature to predator-free offshore islands. There are further reasons for hope. Trapping predators and rearing baby chicks for later release into the wild can have a dramatic effect on kiwi numbers; but it will be necessary to do so on a large scale.
    It would be tragic if New Zealand were to lose its national symbol, the kiwi. Surely the strangest bird in existence, unable to fly, it sniffs out its food with a remarkably strong sense of smell. Its legs are powerful and muscular, for the kiwi is a burrower living in dens—some species even preferring tunnels, yet another similarity it shares with some mammals. But it cannot share its habitat with them without eventually losing the battle for survival.
【R2】
选项 A、 
B、 
C、 
D、 
E、 
答案D
解析 本题所在段讲述了在几千万年前，奇异鸟逐步进化，具有一些哺乳动物的习性。由于在新西兰没有它的天敌，所以数量很多。D项的意思是说明为什么奇异鸟数量众多，符合该段的内容。
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