时差N小时:鸟能识别人类吗?

How dumb, or smart, are birds? Calling someone abirdbrain is usually meant as an insult. But manybirds are quite clever. Take, for example, themockingbird. To you and me, one mockingbird mightlook pretty much like any other. But from the birds'perspective, the same isn't true of humans.

鸟类究竟是愚蠢还是聪明呢?称某人为“鸟脑”通常意味着侮辱。但很多鸟儿其实非常聪明。例如知更鸟。对于你、我来说，所有的知更鸟可能看起来都一样。但是从鸟的角度来看，这一理论却不适用于人类。

Mockingbirds can tell one person from another with great skill, especially when that personposes a threat. In one experiment, scientists had volunteers approached and touchedmockingbird nests once a day for four days. By the second day, the birds began their warningcalls and attack runs sooner than they had the day before. By the fourth day, the birdsappeared to be able to spot the human intruders as soon as they began to approach the nests.

在分辨不同的人方面，知更鸟技巧高超，特别是有人威胁它时。在一项试验中，科学家们让志愿者们去接近、触碰知更鸟的窝巢，每天一次，连续四天。第二天，鸟儿们便鸣叫警告、突袭来者，反应比前一天更迅速。到第四天，一旦志愿者们开始接近鸟巢，知更鸟便能辨别出那位人类入侵者。

On the fifth day, however, a new person approached and touched the birds' nests. And thebirds were slower to react. So in other words, the birds weren't simply protecting their nestswith the same ferocity no matter who approached.

然而到了第五天，换一位陌生面孔的志愿者去接近、触摸鸟巢。知更鸟的反应又慢下来。因此换句话说，鸟类对入侵者也会区别对待，并不会一味地气势汹汹。

They quickly recognized repeat intruders and were quick to target them. Because the newintruder wasn't familiar, the birds took longer to size him up. Mockingbirds might not be theonly bird species to distinguish between people. Other species that have adapted to humanenvironments might be good people spotters, too. In fact, this ability might be part of whatallows some birds to thrive in urban environments.

他们很快地识别重复入侵者，并快速攻击他们。因为对新的入侵者并不熟悉，所以知更鸟要花更长时间来做出判断。知更鸟可能并不是唯一能够区别人类的鸟类。其它一些已经适应了人类环境的鸟类，可能也十分善于识别人类。事实上这种能力会帮助鸟类在现代环境中生存下去。