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科学美国人60秒 SSS Bird Feeders Attract Bird Eaters, Too

时间:2017-03-06 06:57:23

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More than half of U.S. households provide food for birds. It's a billion dollar industry. Now a study asks whether the same feeders that attract birds also attract predators1 that eat the eggs and newly hatched nestlings of those birds. 

“We imagined that the food resource on the landscape could have a couple different effects on relationships between nest predators and their prey2.” Ohio State University researcher Jennifer Malpass.

“On the one hand, you could see that the food might be attracting predators to certain areas, and that could increase nest predation risk. However, predators may be exploiting these food resources, and if you've got a good, predictable food resource on the landscape that's easy for predators to access, you could imagine that they could switch to those anthropogenic, or those human-provided foods, like bird feeders. And that could perhaps lessen3 nest predation risk.”

Which could also be a problem, because predators help control the population.

Malpass and her team looked at the nests of American robins5 and Northern Cardinals7 in seven Ohio neighborhoods. They noted8 the presence or absence of feeders and recorded potential nest predators, like squirrels, domestic cats, and other birds. Over the four-year study, they observed more than 15,000 day-active predators across 19 species, but only brown-headed cowbirds and American crows were associated with bird feeders. The results were published in the journal The Condor9. [Jennifer S. Malpass, Amanda D. Rodewald, and Stephen N. Matthews, Species-dependent effects of bird feeders on nest predators and nest survival of urban American Robins and Northern Cardinals]

The survival of Northern Cardinal6 nestlings did not seem to be related to the presence of these nest predators or even to bird feeders. But the American robins tell a different story.

“In areas that had both many crows and many bird feeders, American robin4 nest survival was the lowest.”

So the effect of bird feeders on urban wildlife communities differs from species to species, neighborhood to neighborhood.

“At least some predators seem to be attracted by bird feeders and the food resource they provide, and in some cases this can lead to increased nest predation risk for native backyard breeding birds.”

But that doesn't necessarily mean that we should get rid of all the bird feeders.

“There are some great ecological10 and social benefits from this practice. We see them as nature's ambassadors. They're a point of connection to nature and the outside world and our native wildlife.”

Homeowners have been feeding wild birds for a long time, but only now are scientists finally beginning to understand just how that affects urban ecosystems11. And the upshot, of course, is: it's complicated.

—Jason G. Goldman

[The above text is a transcript12 of this podcast.]


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1 predators 48b965855934a5395e409c1112d94f63     
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面)
参考例句:
  • birds and their earthbound predators 鸟和地面上捕食它们的动物
  • The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
2 prey g1czH     
n.被掠食者,牺牲者,掠食;v.捕食,掠夺,折磨
参考例句:
  • Stronger animals prey on weaker ones.弱肉强食。
  • The lion was hunting for its prey.狮子在寻找猎物。
3 lessen 01gx4     
vt.减少,减轻;缩小
参考例句:
  • Regular exercise can help to lessen the pain.经常运动有助于减轻痛感。
  • They've made great effort to lessen the noise of planes.他们尽力减小飞机的噪音。
4 robin Oj7zme     
n.知更鸟,红襟鸟
参考例句:
  • The robin is the messenger of spring.知更鸟是报春的使者。
  • We knew spring was coming as we had seen a robin.我们看见了一只知更鸟,知道春天要到了。
5 robins 130dcdad98696481aaaba420517c6e3e     
n.知更鸟,鸫( robin的名词复数 );(签名者不分先后,以避免受责的)圆形签名抗议书(或请愿书)
参考例句:
  • The robins occupied their former nest. 那些知更鸟占了它们的老窝。 来自《现代汉英综合大词典》
  • Benjamin Robins then entered the fray with articles and a book. 而后,Benjamin Robins以他的几篇专论和一本书参加争论。 来自辞典例句
6 cardinal Xcgy5     
n.(天主教的)红衣主教;adj.首要的,基本的
参考例句:
  • This is a matter of cardinal significance.这是非常重要的事。
  • The Cardinal coloured with vexation. 红衣主教感到恼火,脸涨得通红。
7 cardinals 8aa3d7ed97d6793c87fe821585838a4a     
红衣主教( cardinal的名词复数 ); 红衣凤头鸟(见于北美,雄鸟为鲜红色); 基数
参考例句:
  • cardinals in scarlet robes 身披红袍的枢机主教
  • A conclave of cardinals was held to elect the new Pope. 红衣主教团举行了秘密会议来选举新教皇。
8 noted 5n4zXc     
adj.著名的,知名的
参考例句:
  • The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • Jim is noted for arriving late for work.吉姆上班迟到出了名。
9 condor ip1zl     
n.秃鹰;秃鹰金币
参考例句:
  • The condor soars above the mountain heights.禿鹰翱翔于高山之上。
  • A condor prepares to fly in Colombia.一只兀鹰在哥伦比亚准备振翅高飞。
10 ecological IrRxX     
adj.生态的,生态学的
参考例句:
  • The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
  • Each animal has its ecological niche.每种动物都有自己的生态位.
11 ecosystems 94cb0e40a815bea1157ac8aab9a5380d     
n.生态系统( ecosystem的名词复数 )
参考例句:
  • There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
  • Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样,从雨林到半荒漠等不一而足。 来自辞典例句
12 transcript JgpzUp     
n.抄本,誊本,副本,肄业证书
参考例句:
  • A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
  • They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

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