搜索关注在线英语听力室公众号:tingroom,领取免费英语资料大礼包。
(单词翻译)
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.]
1 predators | |
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: |
|
|
2 prey | |
n.被掠食者,牺牲者,掠食;v.捕食,掠夺,折磨 | |
参考例句: |
|
|
3 lessen | |
vt.减少,减轻;缩小 | |
参考例句: |
|
|
4 robin | |
n.知更鸟,红襟鸟 | |
参考例句: |
|
|
5 robins | |
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: |
|
|
6 cardinal | |
n.(天主教的)红衣主教;adj.首要的,基本的 | |
参考例句: |
|
|
7 cardinals | |
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: |
|
|
8 noted | |
adj.著名的,知名的 | |
参考例句: |
|
|
9 condor | |
n.秃鹰;秃鹰金币 | |
参考例句: |
|
|
10 ecological | |
adj.生态的,生态学的 | |
参考例句: |
|
|
11 ecosystems | |
n.生态系统( ecosystem的名词复数 ) | |
参考例句: |
|
|
12 transcript | |
n.抄本,誊本,副本,肄业证书 | |
参考例句: |
|
|
本文本内容来源于互联网抓取和网友提交,仅供参考,部分栏目没有内容,如果您有更合适的内容,欢迎 点击提交 分享给大家。