60秒科学:Whistle While You Wing

Whistle While You Wing
A study in the Proceedings¹ of the Royal Society B finds that pigeon wing-flapping produces distinct whistles, which can warn flock-mates, when merely taking off or when actively² escaping predators⁴. Karen Hopkin reports

When crested⁵ pigeons spot a predator³, they give a little whistle. But the sound doesn’t come from their beaks⁶. And according to a study published by The Royal Society, that whistle warns the rest of the flock to flee.

There’s safety in numbers, and a flock offers protection in part because it has so many eyes watching for danger. But it’s not clear how an individual sounds the alarm when it spots a predator. Maybe anytime one or two birds fly off, they all do. Just in case. Of course that kind of knee-jerk reaction could produce a lot of false alarms. So how can birds tell when their flockmates are seriously headed for the hills?

Scientists recorded the sounds made by the wings of crested pigeons during a routine liftoff (wing sound 1). And the noise their wings make during an emergency takeoff (wing sound 2). And they found that the sound make by wings flapped in terror includes a distinctive⁷ sort of whistle.

That noise alone will scatter⁸ a flock of feeding pigeons just as quick as the shadow of a passing hawk⁹. And gives a whole new meaning to the expression, “on a wing and a prayer.”

—Karen Hopkin

1 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

2 actively   

adv.积极地，勤奋地

参考例句：

• During this period all the students were actively participating.在这节课中所有的学生都积极参加。
• We are actively intervening to settle a quarrel.我们正在积极调解争执。

3 predator   

n.捕食其它动物的动物；捕食者

参考例句：

• The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
• Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴，它是一种令人恐惧的捕食性动物。

4 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

5 crested   

adj.有顶饰的，有纹章的，有冠毛的v.到达山顶（或浪峰）( crest的过去式和过去分词 )；到达洪峰，达到顶点

参考例句：

• a great crested grebe 凤头䴙䴘
• The stately mansion crested the hill. 庄严的大厦位于山顶。 来自《现代英汉综合大词典》

6 beaks   

n.鸟嘴( beak的名词复数 )；鹰钩嘴；尖鼻子；掌权者

参考例句：

• Baby cockatoos will have black eyes and soft, almost flexible beaks. 雏鸟凤头鹦鹉黑色的眼睛是柔和的，嘴几乎是灵活的。 来自互联网
• Squid beaks are often found in the stomachs of sperm whales. 经常能在抹香鲸的胃里发现鱿鱼的嘴。 来自互联网

7 distinctive   

adj.特别的，有特色的，与众不同的

参考例句：

• She has a very distinctive way of walking.她走路的样子与别人很不相同。
• This bird has several distinctive features.这个鸟具有几种突出的特征。

8 scatter   

vt.撒，驱散，散开；散布/播；vi.分散，消散

参考例句：

• You pile everything up and scatter things around.你把东西乱堆乱放。
• Small villages scatter at the foot of the mountain.村庄零零落落地散布在山脚下。

9 hawk   

n.鹰，骗子；鹰派成员

参考例句：

• The hawk swooped down on the rabbit and killed it.鹰猛地朝兔子扑下来,并把它杀死。
• The hawk snatched the chicken and flew away.老鹰叼了小鸡就飞走了。