新托福考试必备：新托福TPO（1-24）听力原文文本TPO11

　　Professor
　　Ok, today we are going to continue our discussion of the parenting behaviors
　　of birds. And we are going to start by talking about what are known as
　　distraction displays. Now if you were a bird and there was a predator around.
　　What are you going to do? Well, for one thing you are going to try to attract as
　　little attention as possible, right? Because if the predator doesn’t know you are
　　there, it is not going to try to eat you. But sometimes certain species of birds do
　　the exact opposite when the predator approaches they do their best to try to
　　attract the attention of that predator. Now why would they do that? Well, they
　　do that to draw the predator away from their nests, away from their eggs or
　　their young birds. And the behaviors that the birds engaging in to distract
　　predators are called distraction displays. And there are a number of different
　　kinds of distraction displays. Most of the time, when birds are engaging in
　　distraction displace they are going to be pretending either that they have injury
　　or that they’re ill or that they’re exhausted. You know something that’ll make
　　the predator thinks Hum… here is an easy meal. One pretty common
　　distraction display was called the broken wing display. And in a broken wing
　　display the bird spreads and drags the wings or its tail, and while it does that, it
　　slowly moves away from the nests so it really looks like a bird with a broken
　　wing. And these broken wing displays can be pretty convincing.

　　Another version of this kind of distraction display is where the birds create
　　same impression of a mouse or some other small animals that running along
　　the ground. A good example of that kind of display is created by a bird called
　　the purple sandpiper. Now what’s the purple sandpiper does is when a
　　predator approaches, it drags its wings but not to give it the impression that its
　　wings are broken but to create the illusion that it has a second pair of legs. And
　　then it raises its feathers, so it looks like it got a coat of fur. And then it runs
　　along the ground swirling left and right you know like running around a little
　　rocks and sticks. And as it goes along it makes a little squeezing noises. So
　　from a distance it really looks and sounds like a little animal running along the
　　ground trying to get away. Again to the predator, it looks like an easy meal.
　　Now what’s interesting is the birds have different levels of performance of
　　these distraction displays. They don’t give their top performance, their prime
　　time performance every time. What they do is they save their best
　　performances they’re most conspicuous and most risky displays for the time
　　just before the baby birds become able to take care of themselves. And the
　　time that way because that when that make the greatest investment in
　　parenting their young. So they are not going to put their best performance just
　　after they laid their eggs because they have to invest that much more time and
　　energy in parenting yet. The top performance is going to come later. Now you
　　have some birds that are quiet mature, are quite capable almost as soon as
　　they hatch. In that case, the parent will put on the most conspicuous
　　distractions displays just before the babies’ hatch because once the babies are
　　hatch they can pretty much take care themselves, and then you have others
　　birds that helpless when have hatch. In that case, the parents will save the
　　best performance until just before the babies get their feathers.