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托福阅读素材:鸟筑巢

2017-09-22编辑: 环球教育整理来自: 环球教育

  很多考生会抱怨托福阅读时间不够,还没完全理解文章就做题,正确率不高。其实这是我们对托福阅读素材不熟悉造成的,下面小编整理了一下托福阅读考试最新的素材,希望能帮助大家更加快速高效的备考托福。

  托福阅读素材:鸟筑巢

  内容回忆:

  大致是先说了鸟喜欢在 colonies 筑巢,并且说了有什么好处,后提及有一种鸟有自我保护意思,可以群体攻击那些天敌,有些 seabird 都在哪里筑巢比较安全,同时,集体筑巢又有什么隐患,例如吸引大量天敌。

  参考阅读:

  Bird Nesting Colonies

  In many species, including herons, swallows, and most seabirds, individual birds come together each year to build nests near the nests of many others of the species. The resulting aggregations are called nesting colonies. Colonial nesting involves a number of factors. Seabirds, for example, often forage widely over the ocean surface, where the only available nesting land may be an island of limited area. The birds may also prefer an island to mainland nesting sites because it is safer, being inaccessible to most land predators. Also, by watching their neighbors returning to the colony with food for their chicks, colony-nesting gulls, or puffins may learn from one another where they can forage most successfully. Bank and Cliff Swallows, for example, build their nests in sites protected from ground predators such as foxes, skunks, and weasels.

  Because residents in a colony usually share their feeding sites, colonial nesters are not, strictly speaking, territorial birds. They do, however, defend their nests against the adjacent birds, and with good reason: Colony members are known to sometimes steal nesting material from one another. They have also been known to sneak eggs into other birds' nests and to seduce other birds' mates. On the positive side, a few colony nesters have been known, on rare occasions, to feed another neighbor's chicks.

  Bird Colonies The habit of nesting in groups is believed to provide better survival against predators in several ways. Many colonies are situated in locations that are naturally free of predators. In other cases, the presence of many birds means there are more individuals available for defense. Also, synchronized breeding leads to such an abundance of offspring as to satiate predators.

  For seabirds, colonies on islands have an obvious advantage over mainland colonies when it comes to protection from terrestrial predators. Other situations can also be found where bird colonies avoid predation. A study of Yellow-rumped Caciques in Peru found that the birds, which build enclosed, pouch-like nests in colonies of up to one hundred active nests, situate themselves near wasp nests, which provide some protection from tree-dwelling predators such as monkeys. When other birds came to rob the nests, the caciques would cooperatively defend the colony by mobbing the invader. Mobbing, clearly a group effort, is well-known behavior, not limited to colonial species; the more birds participating in the mobbing, the more effective it is at driving off the predator. Therefore, it has been theorized that the larger number of individuals available for vigilance and defense makes the colony a safer place for the individual birds nesting there. More pairs of eyes and ears are available toraise the alarm and rise to the occasion.

  Another suggestion is that colonies act as information centers and birds that have not found good foraging sites are able to follow others, who have fared better, to find food. This makes sense for foragers because the food source is one that can be locally abundant. This hypothesis would explain why the Lesser Kestrel, which feeds on insects, breeds in colonies, while the related Common Kestrel, which feeds on larger prey, is not.

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