Narrator: Listen to part of a lecture in a Biology Class.

独白：听一段关于鸟类的生物学讲座。

The class has been learning about birds.

这节课是关于鸟类的。

Professor: OK, today we are going to continue our discussion of the parenting behaviors of birds.

教授：好的，今天我们要继续讨论关于鸟类的哺育行为。

And we are going to start by talking about what are known as distraction displays.

首先我们来谈谈什么是 distraction displays。

Now if you were a bird and there was a predator around.

现在，如果我们是鸟，而周围正有一个捕食者。

What are you going to do?

我们会做什么？

Well, for one thing you are going to try to attract as little attention as possible, right?

首先，你会想要尽量不引起它的注意，对吗？

Because if the predator doesn't know you are there, it is not going to try to eat you.

因为捕猎者如果不知道你在那儿，就不会试着吃掉你。

But sometimes certain species of birds do the exact opposite when a predator approaches, they do their best to attract the attention of that predator.

但有些鸟类的行为恰恰相反，当捕食者靠近的时候，它们想方设法去吸引它的注意力。

Now why would they do that?

为什么它们会这么做？

Well, they do that to draw the predator away from their nest, away from their eggs or their young birds.

它们这么做，是为了将捕食者从它们的巢和里面的幼鸟吸引走。

And the behaviors that the birds engage in to distract predators are called distraction displays.

这种调离注意力的行为，就叫做分散注意力行为（distraction displays）。

And there are a number of different kinds of distraction displays.

有很多种鸟类分散捕食者注意力的方法。

Most of the time, when birds are engaging in distraction displays, they are going to be pretending either that they have an injury or that they're ill or that they're exhausted, you know, something that'll make the predator think "Hum...here is an easy meal".

大多数时间，当一个鸟要进行分散注意力行为的时候，它们会或者假装是受伤了，或者假装是生病了非常疲惫，你知道⋯⋯就是任何一种能让捕食者认为“嗯，这个猎物很好得手”的行为。

One pretty common distraction display was called the broken wing display.

一种比较常见的分散注意力的方法叫做断翅法。

And in a broken wing display, the bird spreads and drags its wing or its tail, and while it does that, it slowly moves away from the nest.

在断翅法中，一只鸟会散开它的翅膀和尾巴，拖拽着移动，它一边这么做，一边慢慢远离自己的巢。

So it really looks like a bird with a broken wing.

看上去跟真的断了翅膀一样。

And these broken wing displays can be pretty convincing.

非常有说服力。

Another version of this kind of distraction display is where the bird creates the impression of a mouse or some other small animal that's running along the ground.

另外一种版本的分散注意力，是鸟类制造了一种假象，好像有老鼠等小动物正在周围。

A good example of that kind of displays is created by a bird called the purple sandpiper.

这种行为的一个很好的例子是由一种叫做紫矶鹞的鸟类演绎的。

Now what the purple sandpiper does is when a predator approaches, it drags its wings, but not to give the impression that its wings are broken, but to create the illusion that it has a second pair of legs.

当一个捕食者在周围时，紫矶鹞做的是，拖拽着翅膀，但并不是要假装翅膀断了，而是为了制造一种（翅膀下面）有另外一双脚的错觉。

And then it raises its feathers, so it looks like it's got a coat of fur.

它还会提升它的羽毛，看上去好像它披着一层绒毛。

And then it runs along the ground, swirling left and right, you know like it's running around a little rocks and sticks.

接着它绕着地上的小石头、小木棍左右摇摆地跑来跑去。

And as it... as it goes along, it makes a little squealing noise.

还发出一些吱吱声。

So from a distance, it really looks and sounds like a little animal running along the ground, trying to get away.

所以从远处看，的确很像是一个小动物在地上逃跑的样子。

Again to the predator, it looks like an easy meal.

同样，这会让捕食者觉得，这是一顿能轻易得手的晚饭。

Now what's interesting is that birds have different levels of performance of these distraction displays.

有趣的是，鸟类的这种分散注意力行为有几个不同的等级。

They don't give their top performance, their prime time performance every time.

它们并不是每次都拿出它们最高超的的手段示人。

What they do is they save their best performances, their most conspicuous and most risky displays, for the time just before the baby birds become able to take care of themselves.

它们在风险达到顶峰的时刻才会使用最厉害的方法，而当幼鸟即将出巢并且有了自理能力的时候，它们所使用的分散注意力的手段就会是（比较粗糙，甚至有点） 冒险的。

And they time it that way because that's when they have made the greatest investment in parenting their young.

因为保护幼鸟需要合理地投入精力。

So they are not going to put on their best performance just after they laid their eggs because they haven't invested that much more time and energy in parenting yet.

所以当鸟类刚下蛋后，它们不会花太多精力做分散注意力的行为，因为它们还有花费更多的精力去哺育幼鸟。

The top performance is going to come later.

高招要稍后再出。

Now you have some birds that are quiet mature, are quite capable almost as soon as they hatch.

而现在，一些幼鸟已经长得比较成熟了，也将在被孵育出的一刻能够自理。

And in that case, the parent will put on the most conspicuous distractions displays just before the babies' hatch because once the babies are hatched they can pretty much take care of themselves, and then you have others birds that are helpless when they hatch.

这种情况下，它们的父母将上演最显眼的分散精力术，在幼鸟即将破壳之前，因为一旦它们破壳而出，就可以照顾自己了，接着就会有其他鸟类来帮助它们孵育。

In that case, the parent will save its best performances until just before the babies get their feathers.

这样，父母就会将最好的分散注意力术一直上演到幼鸟长出羽毛。