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TOEFL Directory > TOEFL writing > TOEFL Reading Class Unit 1_Passage 23_Question 243-253
TOEFL Reading Class Unit 1_Passage 23_Question 243-253
You have about 15 minutes to finish this passage.
First,use about 3-4 minutes to read the passage, try to understand the main idea of this passage.
Don't read it so slowly or try to remember all details.You need to do "fast reading",and "scan" the passage.
Second, read questions 1-11, and with questions you go back the passage again and look for correct answers.
Questions 243-253
Passage 23
There are several problems in accurately determining what bald eagles eat. The best approach is to observe the eagles and identify the prey they capture, but this is often difficult. Most studies use an indirect method for determining dietary habits. The eagle's diet can be reconstructed either by examining food remains at the nest and feeding perches or by analyzing regurgitated pellets, which contain the undigested portions of the food. Pellet analysis is, however, a poor research technique because fish remains are either totally absent from or underrepresented in pellets, since fish are more easily digested than other foods.
The vast diversity of prey that eagles exploit is exemplified by the variety of prey remains found at their nests or under their feeding perches. Also, eagles will feed on prey of any size. Bald eagles are known to eat small rodents, but they also dine on beached whales. Their food habits can change daily or seasonally and from one location to next, and their varied foraging tactics mean that their diet will also be diverse. When eagles steal prey from other predators, for example, they exploit a whole new range of food sources. Perhaps the only restriction the eagle faces is in the location in which it seeks prey. Eagles require large, open expanses of water or land for foraging and feeding.
Bald eagles feed primarily on fish, birds, and mammals. Using information from 20 studies of nesting eagles in North America, an overall average diet can be calculated: 56 percent fish, 28 percent birds, 14 percent mammals, and 2 percent miscellaneous sources. In other words, nesting eagles eat twice as many birds as mammals, but twice as many fish as birds.
When a choice is available, bald eagles invariably select fish over other prey. Preference tests, in which fish, bird, and mammal carrion were placed at feeding areas or provided to captive birds, showed that fish were chosen most often, followed by birds, then mammals. Although fish may be preferred, prior experience can greatly influence a bird's choice. An eagle that has been eating a particular item will likely continue foraging for it as long as it remains available.
243. What aspect of bald eagles does the passage mainly discuss?
a) Diet
b) Nesting behavior
c) Habitat
d) Hunting skill
244. Why is a pellet analysis a poor research technique?
a) The pellets are difficult to locate.
b) The proportion of fish remains is too low.
c) Small rodents eat some of the pellets.
d) The partially digested remains are too damaged to analyze.
245. According to the passage, what is one effect of an eagle stealing prey from other predators?
a) It reduces the time required for hunting.
b) The eagle is able to hunt close to its nest.
c) Other predators are driven away.
d) The variety of food available to the eagle is increased.
246. According to the passage, all of the following factors affect an eagle's choice of food EXCEPT
a) the season of the year
b) the size of the prey
c) what it has been eating recently
d) its normal preferences
247. Given a selection, which of the following would an eagle probably eat first?
b) Fish
c) Rodents
d) Insects
e) Birds
248. The word diversity in the passage is closest in meaning to
a) variety
b) volume
c) region
d) necessity
249. The word next in the passage refers to
a) habits
b) location
c) tactics
d) diet
250. The word expanses in the passage is closest in meaning to
a) areas
b) seasons
c) concentrations
d) studies
251. The word prior in the passage is closest in meaning to
a) significant
b) noticeable
c) past
d) normal
252. The word it in the passage refers to
a) fish
b) experience
c) eagle
d) item
253. According to the passage, the direct method of determining what bald eagles eat is to
a) conduct preference tests
b) monitor prey populations
c) observe eagles foraging in the wild
d) examine food remains at nests
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