VOA慢速英语--研究称失去歌声的小鸟找伴侣的可能性较小

Research: Birds That Lose Their Songs Less Likely to Find a Mate

Young male songbirds usually learn their songs from adult songbirds. But when those young birds do not have older ones to teach them, they have less success attracting mates.

For five years, ecologist Ross Crates¹ with Australian National University has studied the singing ability and mating success of birds called regent honeyeaters. These black and yellow birds were once common across Australia. But loss of their living space since the 1950s has decreased their population to only about 300 or 400 wild birds today.

Male birds once formed large groups in the winter. Now they are spread out across the country, so many fly alone. That means fewer honeyeater adults are nearby during the young birds' first year of life.

"Song learning in many birds is a process similar to humans learning languages — they learn by listening to other individuals," said Crates.

"If you can't listen to other individuals, you don't know what you should be learning."

Researchers found that a large number of male birds appear to be learning tunes³ only used by other species. About 12 percent of male regent honeyeaters end up producing versions of songs usually sung by friarbirds and black-faced cuckooshrikes, among other birds.

The scientists released their research in the publication Proceedings⁴ of the Royal Society B. They found that males who sang unusual songs were less successful in attracting mates.

Peter Marra is a conservation biologist at Georgetown University and was not involved in the study. He said, "This research suggests that the loss of a song language once the population reaches a very small size could accelerate their decline."

The exact reason females do not accept the males was not clear.

Scott Ramsay is a behavioral ecologist at Wilfrid Laurier University in Ontario, Canada. He was not involved in the research. He said the songs were like an advertisement: "When male birds sing, it's like putting out an ad saying, ‘I'm over here...and I'm really interested in finding a partner.'"

Ramsay added that female honeyeaters may not even recognize these unusual singers as possible mates, and so do not approach them. Or it could be that they approach, "but then things go wrong if the males" do not behave as expected.

Most male birds spend several months in their first year learning the songs they will sing for the rest of their lives. Some birds learn from their fathers. But regent honeyeaters leave the nest before they learn to sing, so the males need to find other birds to learn from.

Carl Safina is an ecologist at Stony⁵ Brook⁶ University and also was not involved in the research. He said, "We need to be aware of the importance of preserving song culture in birds...some elements of what these birds need to do to survive isn't instinctive⁷, it has to be learned."

Crates' team has begun putting their findings into action. To help young birds in reproduction programs learn their notes, they have started playing male song recordings⁸. They have also placed skilled male singers next to young learners. The hope is that these experienced birds can pass on their songs to the next generation.

Words in This Story

attract –v. to cause (someone) to like or be interested in something

ecologist –n. a person who studies ecology: the science that deals with the relationships between groups of living things and their environment

tune² –n. a series of musical notes that produce a pleasing or recognizable sound

accelerate –v. to move faster; to gain speed

decline –v. to become less in number or lower in amount

nest –n. a place where birds lay their eggs and raise their young

instinctive –adj. relating to or based on behavior that is not based on thinking or learning

1 crates   

n. 板条箱, 篓子, 旧汽车 vt. 装进纸条箱

参考例句：

• We were using crates as seats. 我们用大木箱作为座位。
• Thousands of crates compacted in a warehouse. 数以千计的板条箱堆放在仓库里。

2 tune   

n.调子；和谐，协调；v.调音，调节，调整

参考例句：

• He'd written a tune,and played it to us on the piano.他写了一段曲子，并在钢琴上弹给我们听。
• The boy beat out a tune on a tin can.那男孩在易拉罐上敲出一首曲子。

3 tunes   

n.曲调，曲子( tune的名词复数 )v.调音( tune的第三人称单数 )；调整；（给收音机、电视等）调谐；使协调

参考例句：

• a potpourri of tunes 乐曲集锦
• When things get a bit too much, she simply tunes out temporarily. 碰到事情太棘手时，她干脆暂时撒手不管。 来自《简明英汉词典》

4 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

5 stony   

adj.石头的，多石头的，冷酷的，无情的

参考例句：

• The ground is too dry and stony.这块地太干，而且布满了石头。
• He listened to her story with a stony expression.他带着冷漠的表情听她讲经历。

6 brook   

n.小河，溪；v.忍受，容让

参考例句：

• In our room we could hear the murmur of a distant brook.在我们房间能听到远处小溪汩汩的流水声。
• The brook trickled through the valley.小溪涓涓流过峡谷。

7 instinctive   

adj.(出于)本能的；直觉的；(出于)天性的

参考例句：

• He tried to conceal his instinctive revulsion at the idea.他试图饰盖自己对这一想法本能的厌恶。
• Animals have an instinctive fear of fire.动物本能地怕火。

8 recordings   

n.记录( recording的名词复数 )；录音；录像；唱片

参考例句：

• a boxed set of original recordings 一套盒装原声录音带
• old jazz recordings reissued on CD 以激光唱片重新发行的老爵士乐