英语听力精选进阶版 7340（在线收听）

据一项研究调查显示电子产品可能对某些鸟类的迁徙产生影响。一组德国科研人员发现由电子设备和广播信号制造的电磁场会影响鸟类的方向感。这项研究发表在《自然》杂志上。

Some birds perform remarkable feats of navigation, migrating halfway around the world. And it’s thought that a built-in compass, which senses the Earth's magnetic field, helps them to find their way.

But this latest study suggests that low frequency waves produced by devices plugged into the mains electricity, could be interfering with this 'inner satnav'. Scientists found that migratory birds exposed to this electromagnetic noise lost all sense of direction. But when the field was blocked out, they found their bearings again.

Researchers believe electrical interference could be a particular problem when birds fly over urban areas. They think the birds are forced to switch to back-up navigational systems, staying on course using the sun and stars instead.

Quiz 听力测验

1. What has been disrupting the sense of direction of some birds?

Low frequency waves produced by equipment plugged into mains electricity.

2. What happened when the source of the problem was eliminated?

The birds found their bearings again.

3. When does the problem become particularly difficult?

When the birds fly over urban areas.

4. What do birds use as a back-up system?

They use the position of the sun and the stars to find their way.

Glossary 词汇表

remarkable 非凡的，非常好的

compass 指南针

mains electricity 主流电源

satnav （卫星）导航仪

found their bearings 找到它们的方向

back-up 应急的、备用的