A recent study by a team of researchers from Canada has uncovered that birds living in cities are not just better at problem solving and more skilled in tasks than those in the countryside: they also have stronger immune（有免疫力的）systems !
The research, headed by Audet, a Ph. D. student at a university, examined the cognitive （认知的）abilities of city birds with those of their country cousins. The team did their study in Barbados because it needs a broad range of situations: from crowded modern cities to the countryside. They began by catching some birds from various parts of the Caribbean Island. The birds were then given several tasks. Some tested their associative learning skills while others were to observe how creative they were at problem-solving. While country birds are also much braver, the city birds appeared to be more careful when facing unfamiliar things.
The results did not surprise the researchers. After all, birds living in cities and towns face many more challenges and dangers than those that live in the country. But as it turns out, the city birds proved to have better immunity and are therefore more resistant （抵抗的）to diseases than those living in the countryside. While additional studies need to be done to see if this is true for all city birds, there is no reason to believe that the results would be any different.
Though this is the first time researchers have compared the cognitive abilities of birds living in different conditions, it is not the first study to examine the differences between city and country birds. Previous research has shown that blackbirds in cites are similarly more careful than country blackbirds, and that sparrows and blackbirds living in cities sing at a higher frequency to be heard over city noise and to make up for sound distortions（失真）caused by tall buildings. If only birds knew the advantages of living among humans, maybe more would move to cities!
【小题1】How are city birds different from country birds according to the research?| A．City birds have a weaker immune system because of air pollution. |
| B．City birds are braver when facing unfamiliar things or situations. |
| C．Country birds are less skilled at jobs requiring creation and skills. |
| D．Country birds have a wider range of challenges to survive. |
| A．Country birds can be taught the advantage of living in cities. |
| B．City birds are more resistant to diseases than country birds. |
| C．City birds are more likely to get sick than country birds. |
| D．Country birds are more careful in dangerous situations. |
| A．There're more dangers in cities for them. |
| B．The birds live far away from each other. |
| C．There are a wider range of situations. |
| D．There's too much noise in the city. |
| A．Research into birds' immune system and learning power. |
| B．City birds are smarter and healthier than country birds. |
| C．What a PhD. student has done has surprised the world. |
| D．The necessity and ways to move country birds to cities. |
