A
It’s hard to be a bird in a world which is in the charge of mankind.
You can hardly hear yourself sing, let alone hear the songs of your friends… and worst of all, you can’t hear a predator(捕食者). Noise is almost everywhere, especially noise from traffic.
Researchers have tried to study the influence of road noise on animals by looking at animals living near noisy roads.
“We figured out a way to have just the noise without any of the other effects of the road, and to do that we put many speakers in a forest where there was no road,” said Chris McClure, a biologist at Boise State University and The Peregrine Fund. He and his team carried out their experiment at a place popular with birds in Idaho as they fly south for the winter.
While the noise kept lots of birds away, some remained. But they had trouble putting on enough weight to support them in the next part of their migratory journey.
“They have to take food but they also have to avoid getting eaten by a predator. But these two things can’t be done at the same time because to eat, they have to look down, which means they aren’t looking at predators.”
And when it’s too loud, they can’t hear the alarm calls of other birds. So they have to waste time looking for predators instead of searching for food.
By 2050, it’s thought that enough new roads will be built to circle the planet more than 600 times. But there’s an easy solution to the noise problem—“Lowering speed limits does a lot.”
So next time you’re driving through nature, just slow down a little. It’s safer for you and the wildlife. And you can enjoy the view a little longer.
21. Who does the word “you” in Para 2 refer to?
A. A driver. B. A predator. C. A researcher. D. A bird.
22. Why did the researchers do the experiment in a forest without roads?
A. To prevent birds from being hit by cars.
B. To separate noise from other effects of the road.
C. To test a larger number of birds.
D. To put as many speakers as possible.
23. Why can’t birds put on enough weight with much noise around?
A. They can’t concentrate on looking for food.
B. They have to fly south for the winter.
C. They can’t hear the alarm calls.
D. They feel afraid of the noise.
24. What is advised to do to protect birds from the noise problem?
A. To build enough new roads.
B. To carry out more experiments.
C. To enjoy the view a little longer.
D. To drive slowly through nature.
