概括：内容选自老托福听力，是练习托福听力的绝佳材料。


Hints:
Miller
Hawk Mountain Sanctuary
Appalachian Mountains
Delaware River

怎么回事儿？挺带感嘛~
As Dr. Miller mentioned, we're trying to recruit volunteers for the Hawk Mountain Sanctuary. But before I get into the details of the volunteer program, I'd just like to tell you a little about what we do there. One of our main jobs is to keep detailed records of the migration patterns of raptors. For those of you who don't know, raptors are birds of prey, like hawks and eagles. Between August and December, we see around 20 different species migrating from Canada and New England - about 20,000 birds. Part of what attracts them to Hawk Mountain is the location on the east ridge of the Appalachian Mountains. What happens is that the sun warms the ridge in such a way that air currents are formed. The birds just sort of glide along on the air, so they use up very little energy. As volunteers you'll be helping us keep accurate counts of the raptors. Any drop in number could mean something's gone wrong in the environment, because of pesticides or disease, even hunting. We just had a scare with the broad-winged hawks. Their numbers have dropped drastically over the last ten years. It was suggested that the birds may have changed their migratory route. So for 11 days we had several hundred volunteers - stationed every five miles - to observe and count. And sure enough, they discovered that instead of hugging the Appalachians as they'd always done. The broad-wings were cutting a wide path over the Delaware River. Needless to say, we were greatly relieved.
像医生米勒所提及的我们正试着为鹰山保护区招募志愿者。但是在我们要告诉你们一些志愿者程序的细节前，我只是想讲一些关于我们所做。 我们的主要工作之一是做猛禽类的迁徙模式的明细记录。因为有些不知道的，猛禽类也是被捕食者，像鹰和大雕。在八月和十二月，我们从加拿大和新英格兰的大约20,000鸟中要看20种不同种类的猛禽类的迁徙。 那些吸引它们到鹰山一部分是位于阿巴拉契亚山脉以东的山脉。太阳温暖了这段山脉并形成了气流。鸟可以沿着气流稍稍滑行，所以它们可以消耗非常少的能量。 作为志愿者你将帮助我们精确猛禽类的数量。数量上的下降可能意味着在这里的环境变得糟糕，由于杀虫剂，病毒，甚至捕猎。 我们仅仅能吓唬那些大翅膀的老鹰。他们数量在近十年间迅速的下降。这显示鸟群可能已经改变了它们的迁徙路径。所以这11天我们已经有了数百的志愿者，每五米驻扎去观察和计数。而且果真，他们发现了代替一直拥抱的阿巴拉契亚山脉。大翅膀们在德瓦拉河上空切开了一道宽录。不必多说，我们非常放心。 ——译文来自: freedomtory