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科学家解开鸟群秘密

How can flocks of birds, schools of fish or herds¹ of antelope² suddenly change direction -- all the individuals adjusting their movement in concert, at seemingly the same time? British researchers now have some insights into this behavior, which has puzzled scientists for a long time.

为什么鸟群、鱼群或是羚羊群中的成员会全体协调，突然同时改变方向？如今，英国的研究人员对这个困扰科学家多年的行为有了一些了解。

A large flock of starlings performs its endless random³ dance above a beach in southern England, constantly changing direction as if commanded by a leader. Their movements resemble an organized structure -- but careful observations fail to identify the one bird that all the others follow.

在英国南方的一个海滩上空，一大群燕八哥无休无止地上演着它们的自由舞步，不断地改变方向，仿佛有一个首领指挥着它们。它们的动作类似一个有组织的结构，但是研究人员经过细致观察，还是辨别不出谁是领头鸟。

A group of scientists at the University of Warwick say that's because of birds' instinctive⁴ need to maintain optimal⁵ density⁶ of the flock, in order to be able to see through it and watch for predators⁸, while keeping the flock together.

华威大学（University of Warwick）的一组科研人员说，这是因为鸟类出于本能，需要维持最佳群体密度，从而使它们既能保持视线通畅，看到捕食者，又保持鸟群不散。

The lead researcher of the study, Daniel Pearce, said every bird in the flock has the same set of information.

丹尼尔?皮尔斯是研究组的首席研究员。他说鸟群中的每只鸟都有着相同的一组信息。

“So it's like lots of individuals independently choosing to behave in a way that from the outside looks like a very organized structure, but it's actually lots of individuals doing the same thing at the same time,” said Pearce.

他说：“这好像是很多不同的个体，彼此独立地选择了这样一种行为方式，让它们从外部看起来仿佛是一个组织非常有序的结构，但实际上，这是很多个体同时做着同样的事情。”

Starlings' flight

In video recordings⁹, starlings pursued by a predatory bird showed similar behavior.

从记录下的视频中可以看出，被一只猛禽追逐的燕八哥们也表现出相似行为。

This was further confirmed by a computer model algorithm simulating a flock of starlings in flight.

一个模仿飞行中的燕八哥鸟群的计算机模型运算进一步证实了这一点。

“Because the flock is always marginally opaque¹⁰, the individuals are more likely to be able to see the predator⁷, they're more likely to see the responses of other birds to the predator, and also because they're always trying to keep this high information within their view they always come back together, so the predator is unable to permanently¹¹ split the flock up,” said Pearce.

他说：“因为鸟群对视线的阻挡总是保持在微乎其微程度，鸟儿们更有可能看到捕食者，它们更有可能看到其他鸟儿们对捕食者的反应，而且，也是因为它们总是试图把这种重要信息留在自己的视野之内，它们总是会回到一起，这样一来，捕食者就没有办法长久地把鸟群拆开。”

Schools of fish

Physics professor Matthew Turner said what works in the air could work in the water.

“Fish are a little bit different to birds, in that they have other senses. They can measure pressure, for example, but basically they're still visually-based organisms. They look at one another as they move, so we are optimistic that a very similar model could also explain the behavior of fish,” said Turner.

他说： “鱼类和鸟类有一点不一样，它们有不同的感觉器官。例如，鱼类可以感测到压力，但是基本上它们还是以视觉为基础的生物。它们移动时，会看着其他同类，所以，我们乐观地相信，我们可以使用非常相似模型，分析出鱼类的行为。”

Scientists say understanding the behavior of birds may help them create algorithms to direct flocks of small robots, tasked with forming certain shapes or objects.

科研人员说，理解鸟类的行为可以帮助他们设计出算法，指挥一群小型机器人，让它们完成组合特定形状或物体的任务。