鸟的地图与指南针

周波

Directions：Read the following passage. Answer the questions according to the information given in the passage and the required words limit.

Even bird brains can get to know an entire continent—but it takes them a year of migration to do so，suggests a Princeton research team.

The scientists have shown that migrating adult sparrows can find their way to their winter nesting grounds even after being thrown off course by thousands of miles.

The team first brought 30 sparrows to Princeton from northern Washington State，where the birds had been in the process of migrating southward from their summer breeding grounds in Alaska. Half the birds were juveniles（少年）of about three months in age that had never migrated before，while the other half were adults that had made the round trip to their wintering site in the south-western United States at least once.

After the birds were released，they attempted to start their migration again but both age group grew disoriented（迷失方向）quickly.

“All the birds scattered（分散）at first，”Wikelski said.“It was clear that they were turned around for a couple of days. But while the adults eventually realized they had to head southwest，the younger birds began flying straight southward again as though they were still in Washington.”

“The adults，”said team member Richard Holland，“recovered their bearings because they possess something the younger birds do not，which is an internal map.”

“These birds need two things to know where they are and migrate effectively：a‘map and a‘compass，”said Holland，a postdoctoral research associate in Wikelskis lab.“What weve found is that juveniles use their compass，but the adults also use their map.”

Holland said，“The birds do not lose the compass as they age，but somehow develop the map，eventually applying both tools to keep on track during migratory flights. Scientists already have determined that the compass is based on the sun or the magnetic field，but where the map comes from remains a mystery—one that the team will be exploring in the coming years.”

1. Where do you think the 30 sparrows spent their summer？（No more than 2 words）

2. What are the juvenile sparrows really lack of？（No more than 3 words）

3. What are scientists still not sure about？（No more than 6 words）

4. What is the main idea of the passage？（No more than 12 words）

参考答案

1. In Alaska.

2. An internal map.

3. What a“map”is based on.

4. Sparrows need both a“map”and a“compass”in migratory flights.

编辑/梁宇清