SSS 2009-09-03
时间：2019-01-08 作者：英语课 分类：Scientific American(九)月
When crested 1 pigeons spot a predator 2, they give a little whistle. But the sound doesn’t come from their beaks 3. 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 distinctive 4 sort of whistle.
That noise alone will scatter 5 a flock of feeding pigeons just as quick as the shadow of a passing hawk 6. And gives a whole new meaning to the expression, “on a wing and a prayer.”
—Karen Hopkin
- 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》
- 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。
- 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
- 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。
- 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。