在线英语听力室_免费在线英语听力学习网站

This is Scientific American's 60-second Science, I'm Christopher Intagliata.

这里是科学美国人——60秒科学系列，我是克里斯托弗·因塔格里塔。

The barred owl¹ has a very distinctive² call.

横斑林鸮的叫声非常独特。

"It's the one that goes, 'Who cooks for you?'"

“听起来就像在说‘谁给你做饭？’”

(CLIP: Barred owl call sample)

（音频剪辑：横斑林鸮的叫声样本）

Connor Wood is a conservation biologist and applied³ ecologist at the University of Wisconsin–Madison—who does a pretty great barred owl impression himself.

威斯康星大学麦迪逊分校的保护生物学家和应用生态学家康纳·伍德说到，他本人恰巧能非常形象地模仿横斑林鸮的叫声。

(CLIP: Impression of barred owl)

（音频剪辑：模仿横斑林鸮）

Barred owls⁴ are native to the eastern U.S. But in the last century, they've crossed the Great Plains, flooded into Canada and taken up roost in the Pacific Northwest, where they're a major threat to northern spotted⁵ owls.

横斑林鸮是美国东部的本土鸟类。但在上个世纪，它们飞跃大平原，涌入加拿大，在太平洋西北部安家，现在它们已成为北方斑点鸮的主要威胁。

"Barred owls are bigger and more aggressive. And so barred owls have been able to basically drive spotted owls out of their preferred nesting areas. And also, because they're more flexible with what they eat, there can be more barred owls on the landscape."

“横斑林鸮体型更大，攻击性也更强。因此，横斑林鸮能将北方斑点鸮赶出它们喜欢的筑巢地点。而且，由于横斑林鸮的食物范围更灵活，因此其在环境中的数量可能会更多。”

And now they're invading the Sierra Nevada mountains, further south—the native range of the California spotted owl.

现在，它们正在入侵更南边的内华达山脉，即加州斑点鸮的原生地。

"And the big question was: What is the size of the barred owl population there, and how fast is it growing?"

“重要的问题是：那里的横斑林鸮数量有多少，增长速度有多快？”

To answer that, Wood and his team deployed⁶ audio recorders in roughly 1,000 locations throughout 2,300 square miles of the northern Sierra Nevada. And then they listened—for two years—collecting the faint calls of spotted owls...

为了回答这个问题，伍德及其团队在遍布内华达山脉北部2300平方英里的近1000个地点部署了录音机。之后他们听了两年录音，并收集了北方斑点鸮模糊的叫声。

(CLIP: Spotted owl)

（音频剪辑：北方斑点鸮的叫声）

...and barred owls, too.

……还有横斑林鸮的模糊叫声。

(CLIP: Barred owl)

（音频剪辑：横斑林鸮）

In total, they gathered 200,000 hours worth of audio.

他们总共收集了20万小时的音频。

"It was pretty daunting⁷, seeing it all accumulate and knowing we had to make something intelligible⁸ out of it."

“看着音频不断积累，我们知道我们必须从中找到一些可以理解的东西，这真是令人气馁。”

Algorithms that combed the audio for owl calls helped make sense of it all, and through models, the researchers were able to estimate who was living in those forests—barred owls or spotted owls—and approximately how many of them there were.

梳理鸮叫录音的算法有助于我们理解这一切，通过模型，研究人员能够估算出生活在森林里的是横斑林鸮还是北方斑点鸮，以及它们的大致数量。

"The key finding is that barred owls occupied about 8 percent of the northern Sierra Nevada landscape in 2017. But that jumps to 21 percent in 2018. So that's a 2.6-fold increase in just one year. On one hand, that's really worrying, because it suggests that barred owl population has begun to grow really rapidly and thus poses an immediate⁹ threat to California spotted owls. But on the other hand, it's also really exciting. 'Cause thta's means we've caught the problem early and have a chance to do something about it. Most biological invasions aren't fully¹⁰ identified until it's too late."

“关键发现是，2017年，横斑林鸮在内华达山脉北部环境中的占有率约为8%。但到2018年，这一比例飙升至了21%。仅用一年就增长了2.6倍。一方面，这确实令人担忧，因为这表明横斑林鸮开始快速增长，继而会对加州斑点鸮构成直接威胁。但另一方面，这也很令人兴奋。因为这说明我们在早期就发现了问题，有机会采取行动。大多数生物入侵，在完全确认时都为时已晚。”

The results are in the journal The Condor¹¹: Ornithological¹² Applications.

这项研究结果发表在《秃鹰：鸟类学应用》期刊上。

Wood and his team advise that it might be necessary to take lethal¹³ action: remove the barred owls before they wipe out California spotted owls. Assuming we give a hoot¹⁴ about the spotted owls' survival.

伍德及其团队建议，可能有必要采取致命行动：清除横斑林鸮，以避免其消灭加州斑点鸮。前提是我们在意加州斑点鸮的生存。

Thanks for listening for Scientific American's 60-second Science. I'm Christopher Intagliata.

谢谢大家收听科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。