Among the species of seabirds that use the windswept cliffs of the Atlantic coast of Canada in the summer to mate, lay eggs and rear their young are common murres, Atlantic puffins, black-legged kittiwakes, and northern gannets. Of all the birds on these cliffs, the black-legged kittiwake gull is the best suited for nesting on narrow ledges. Although its nesting habits are similar to those of gulls that nest on flat ground, there are a number of differences related to the cliff-nesting habit. The advantage of nesting on cliff is the immunity it gives from foxes, which cannot scale the sheer rocks, and from ravens and other species of gulls which have difficulty in landing on narrow ledges to steal eggs. This immunity has been followed by a relaxation of the defences, and kittiwakes do not react to predators as fiercely as do ground-nesting gulls. A colony of Bonaparte’s gulls responds to the appearance of a predatory herring gull by flying up as a group with a clamour of alarm calls, followed by concerted mobbing, but kittiwakes dimply ignore herring gulls, since they pose little threat to nests on cliffs. Neither do kittiwakes attempt to conceal their nest. Most gulls keep the nest area clear of dropping, and remove empty eggshells after the chicks have hatched, so that the location of the nest is not given away. Kittiwakes defecate over the edge of the nest, which keeps it clean, but this practice, as well as their tendency to leave the nest littered with eggshells, makes its location very conspicuous. On the other hand, nesting on a narrow ledge has its own peculiar problems, and kittiwake behaviour has become adapted to overcome them. The female kittiwake sits when mating, whereas other gulls stand, so the pair will not overbalance and fall off the ledge. The nest is a deep cup, made of mud or seaweed, to hold the eggs safely, compared with the shallow scrape of other gulls, and the chicks are remarkably immobile until fully grown. They do not run from their nests when approached, and if they should come near to the cliff edge, they instinctively turn back.
- What aspect of the kittiwake gull does the passage mainly discuss?
A. Its defensive behaviour. B. Its mating season
C. Its nesting habits. D. Its mating habit.
- The word ‘it’ in line 6 refers to _______.
A. immunity B. cliff-nesting habit C. advantage D. nesting
- The word ‘relaxation’ in line 8 is closest in meaning to _______.
A. negligence B. weakness C. liberation D. immobility
- The word ‘scale’ in line 6 is closest in meaning to _______.
A. climb B. avoid C. approach D. measure
- The word ‘immunity’ in line 7 is closest in meaning to _______.
A. distance B. transition C. protection D. reminder
- Why is it difficult for ravens to steal the kittiwakes’ eggs?
A. The kittiwakes can see the ravens approaching the nest.
B. The ravens find it difficult to reach the narrow ledges where kittiwakes nest.
C. The kittiwakes’ eggs are too big for the ravens to carry.
D. The female kittiwakes rarely leave the nest.
- The author mentions that eggshells litter the nests of kittiwakes in order to .........................................
A. demonstrate that kittiwakes are not concerned about predators.
B. prove how busy kittiwakes are in caring for their offspring.
C. show a similarity to other types of gulls.
D. illustrate kittiwakes’ lack of concern for their chicks.
- Which of the following statements is TRUE?
A. Kittiwakes cannot defend themselves from predators.
B. Gulls and kittiwakes have the same nesting habits.
C. Gulls and kittiwakes have the same mating habits.
D. Kittiwakes can raise their offspring.
- Which of the following things doesn’t help to make the gull’s nest less conspicuous?
A. Keeping its nest away from its droppings.
B. Throwing away eggshells after its young have come into existence.
C. Filling its nests with eggshells.
D. Making its nest out of the areas with its waste.
- The word ‘conspicuous’ in line 15 is closest in meaning to _______.