– 100 REFER TO THE FOLLOWING LECTURE/ DISCUSSION PROFESSO...

Questions 96 – 100 refer to the following lecture/ discussion

Professor: Shall we continue with our next topic? I’d like to discuss bird migration now.

We all know that birds migrate South in winter and North in spring. “Does

anyone know why they do that?”

Student 1

: They're looking for warmer weather, right?

Professor: Well … That's part of the reason. But there's another one, too. Anyone else?

Student 2: Uh, they're looking for food?

Professor: Precisely. Many scientists have researched bird n1igration and have come up

with their own theories on why birds migrate. Not all of them, uh, agree with

each other. However, there's one thing they all agree on: Bird migration is

basically about finding food sources. Of course, there are other reasons. For

instance, birds need to reach warmer climates to avoid freezing. Also, they

need safe places, uh, to breed. There are other theories, too. But, when you get

down to it, birds migrate because of food. It's the driving force behind them

flying, in some cases, thousands of miles.

So, what happened to the food in the places the birds were before they migrated

. .. ?

Well, think about it. As winter comes, most vegetation dies. The ground

freezes, and, in many places, there's snow on the ground. This makes foraging

hard or even impossible. Simply put, finding food becomes incredibly difficult.

However, when birds head south, they go to places that are warm even in

winter. Therefore, there are more, urn, sources of food for them. This provides

them with nourishment and decreases their chances of starving. As for the few

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International University – VNU-HCMC, Official handbook for the English Test, page 58

birds that, for whatever reason, fail to migrate, many actually succumb to

starvation.

Student 2: Are there really no food sources in northern climes during winter?

Professor: Well, sure, there are some. But remember that the amount of food available

decreases. As a result, many animals compete for dwindling amounts of food.

What happens is that some birds can find food while most others cannot.

Therefore, most birds avoid this issue by migrating to places with an

abundance of food.

International University – VNU-HCMC, Official handbook for the English Test, page 59