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Question 09-19 The benefits of birds roosting communally (全對！)

Birds that feed in flocks commonly retire together into roosts. The reasons for roosting

communally are not always obvious, but there are some likely __benefits__. In winter

especially, it is important for birds to keep warm at night and conserve precious food

__reserves__. One way to do this is to find __a sheltered roost__. Solitary roosters shelter in

dense vegetation or enter a cavity - horned larks dig holes in the ground and

ptarmigan burrow into snow banks - but the effect of sheltering is magnified by

__several birds huddling together in the roosts__, as wrens, swifts, brown creepers,

bluebirds, and anis do. Body contact reduces the surface area exposed to the cold air,

so the birds keep each other warm. Two kinglets huddling together were found to

reduce their heat losses by a quarter and three together saved a third of their heat.

The second possible benefit of communal roosts is that they act as "information

centers." During the day, parties of birds will have spread out to forage over a very

large area. When they return in the evening some will have fed well, but others may

have found little to eat. Some investigators have observed that when the birds set out

again next morning, those birds that did not feed well on the previous day appear to

follow those that did. The behavior of common and lesser kestrels may illustrate

different feeding behaviors of similar birds with different roosting habits. The common

kestrel hunts vertebrate animals in a small, familiar hunting ground, whereas the very

similar lesser kestrel feeds on insects over a large area. The common kestrel roosts and

hunts alone, but the lesser kestrel roosts and hunts in flocks, possibly so one bird can

learn from others where to find insect swarms.

Finally, there is safety in numbers at communal roosts since there will always be

a few birds awake at any given moment to give the alarm. But this increased protection is

partially counteracted by the fact that mass roosts attract predators and are especially

vulnerable if they are on the ground. Even those in trees can be attacked by birds of

prey. The birds on the edge are at greatest risk since predators find it easier to catch

small birds perching at the margins of the roost.

9. What does the passage mainly discuss?

   (A) How birds find and store food.

   (B) How birds maintain body heat in the winter.

   (C) Why birds need to establish territory.

   (D) Why some species of birds nest together.

10. The word "conserve" in line 3 is closest in meaning to

   (A) retain

   (B) watch

   (C) locate

   (D) share

11. Ptarmigan keep warm in the winter by

   (A) huddling together on the ground with other birds.

   (B) Building nests in trees.

   (C) Burrowing into dense patches of vegetation

   (D) Digging tunnels into the snow.

12. The word "magnified" in line 6 is closest in meaning to

   (A) caused

   (B) modified

   (C) intensified

   (D) combined

13. The author mentions kinglets in line 9 as an example of birds that

   (A) protect themselves by nesting in holes.

   (B) Nest with other species of birds

   (C) Nest together for warmth

   (D) Usually feed and nest in pairs.

14. The word "forage" in line 12 is closest in meaning to

   (A) fly

   (B) assemble

   (C) feed

   (D) rest

15. Which of the following statements about lesser and common kestrels is true?

   (A) The lesser kestrel and the common kestrel have similar diets.

   (B) The lesser kestrel feeds sociably but the common kestrel does not.

   (C) The common kestrel nests in larger flocks than does the lesser kestrel.

   (D) The common kestrel nests in trees, the lesser kestrel nests on the ground.

16. The word "counteracted" in line 24 is closest in meaning to

   (A) suggested

   (B) negated

   (C) measured

   (D) shielded

17. Which of the following is NOT mentioned in the passage as an advantage derived by birds that huddle together while sleeping?

   (A) Some members of the flock warm others of impending dangers.

   (B) Staying together provides a greater amount of heat for the whole flock.

   (C) Some birds in the flock function as information centers for others who are looking for food.

   (D) Several members of the flock care for the young.

18. Which of the following is a disadvantage of communal roosts that is mentioned in the passage?

   (A) Diseases easily spread among the birds.

   (B) Groups are more attractive to predators than individual birds.

   (C) Food supplies are quickly depleted

   (D) Some birds in the group will attack the others.

19. The word "they" in line 25 refers to

   (A) a few birds

   (B) mass roosts

   (C) predators

   (D) trees

註釋

• 全文主旨： The benefits of birds roosting communally
  • keep warm at nihgt

    sheltered roost

    the effect of sheltering is magnified by several birds huddling together in the roosts

    Body contact reduces the surface area exposed to the cold air

  • information center

    those birds that did not feed well on the previous day appear to follow those that did.

    • example: common and lesser kestrels
  • safety

    there will always be a few birds awake at any given moment to give the alarm

    But this increased protection is partially counteracted by the fact that mass roosts attract predators

題解

DADCC CBBDB B

9. 本文主旨： The benefits of birds roosting communally, why some species of birds nest together

10. converse ≒ retain

11. ptarmigan burrow into snow banks

12. magnified ≒ intensified

13. Two kinglets huddling together(nest together) were found to reduce their heat losses(for warmth) ...... .

14. forage ≒ feed

15. The common kestrel roosts and hunts alone(but the common kestrel does not),

      but the lesser kestrel roosts and hunts in flocks (the lesser kestrel feeds sociably)

16. counteracted ≒ negated (counter: 反， act： 作用)

17. (A)(B)(C) 都有提及

18. But this increased protection is partially counteracted by the fact that mass roosts attract predators

19. But this increased protection is partially counteracted by the fact that mass roosts attract predators

      and are especially vulnerable if they are on the ground.

單字

• flock 羊群;(飛禽,牲畜等的)群 a group of sheep, goats, or birds
• roost N: 棲木;鳥巢 V: 棲息;進窩

  N: a place where birds rest and sleep V: f a bird roosts, it rests or sleeps somewhere

  somebody's chickens come home to roost 後遺症發作了 After years of overspending, the chickens have come home to roost.

• communal 公共的;社區的;共有的 (community) shared by a group of people or animals, especially a group who live together
• conserve 保存;保護;節省 (preserve) to protect something and prevent it from changing or being damaged
• reserve V:儲備,保存;保留;預訂 N:儲備(物);儲備金;保留(物);儲藏量

  V: to keep part of something for use at a later time during a process N: a supply of something kept to be used if it is needed

• shelter N: 遮蓋物;躲避處;避難所 V: (使)掩蔽,遮蔽;庇護;保護(+from)

  N: a place to live, considered as one of the basic needs of life V: to provide a place where someone or something is protected

• solitary 非群居的;獨自的 (solo) doing something without anyone else with you
• vegetation 植被;(總稱)植物;草木 plants in general
• cavity 洞,穴 a hole or space inside something
• burrow 挖洞;住入地洞;躲藏起來 (bury) to make a hole or passage in the ground
• bank (形似堤岸的雲,雪,土)堆,一堆;一團(雲,雪,泥等) a large sloping mass of earth, sand, snow etc
• huddle 擠作一團;聚在一起(+together)

  if a group of people huddle together, they stay very close to each other, especially because they are cold or frightened

• party 一團人,一夥人,一行人 a group of people who go somewhere together or do a job together
• whereas 然而 conj (while)
• swarm (昆蟲等的)群;蜂群
• counteract 對...起反作用 (counter-: 反)
• prey 被捕食的動物;補食

  bird of prey 肉食性鳥類 a bird which lives by killing and eating other animals

• preching 飛落,棲息 if a bird perches on something, it flies down and sits on it
• impending 即將發生的;逼近的 an impending event or situation, especially an unpleasant one, is going to happen very soon

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