10 . Street lights can change the amount and quality of sleep that pigeons (鸽子) get at night, affecting their energy in the morning. “More and more studies show how light pollution is affecting animal behavior,” said Anne Aulsebrook, a researcher from the University of Melbourne. “One of the most common and well-documented things light pollution seems to do is cause animals, particularly birds, to change the timing of their behavior.”

Aulsebrook said she chose pigeons because so much was already known about their sleep compared to other birds’, and plenty of them were in captivity (圈养) to study. They set up experiments exposing the birds to darkness one night, switching on the lights the next night and turning them off the following night.

Using sensors that recorded brain and muscle activity, the team found that the pigeons slept for about 10 hours with the lights off. With the lights on, their sleep dropped to about six hours. Quality of sleep was also affected. The pigeons didn’t seem to recover from the loss of rapid-eye movement sleep the night before, slept less intensely the following night and woke up more often. Comparing amber (琥珀色) light to white light, the team found the tone made no difference in sleep patterns.

“If we had to choose, I’d still go with warmer, amber colors,” she said. “The other simpler solution is to turn the lights off.” Other efforts to reduce light pollution include shielding (给……加防护罩) lights, directing them, dimming them or using sensors to turn them on only when people are around.

“More research needs to be done to understand the effects of sleep loss on birds,” Aulsebrook said. “We know that sleep is really important to humans. We experience how important sleep is when we don’t get enough of it,” she said. But there hasn’t been much research in this area on birds. “I think the next big step is looking at whether we can measure these costs of reproduction (繁殖) in these birds if they’re not getting enough sleep,” she said.

1. Which is a proven influence of light pollution on birds?

A．Making them more active.

B．Changing their biological clock.

C．Increasing their tendency to attack.

D．Improving their environmental adaptability.

2. Why did Aulsebrook choose pigeons as research subjects?

A．There is a personal preference for them.

B．There’ll be easily available data on them.

C．They are the most commonly seen birds in life.

D．They have typical sleep patterns for research.

3. What did Aulsebrook’s team find from their research?

A．Lights’ influence on birds’ sleep varies from color to color.

B．Birds tend to be more nervous in the light conditions.

C．Lights do great harm to pigeons’ sleep.

D．Pigeons have an irregular sleeping habit.

4. What is Aulsebrook’s attitude towards the effects of birds’ loss of sleep?

A．Objective.

B．Doubtful.

C．Optimistic.

D．Subjective.