1. GREATEST mysteries / BIRD life / migration / one of the / of / is

2. ringing / of the /on migration /most / has come / from / information / young and adult birds

3. stamped with / a light aluminium ring / a number and RETURN address / is fastened I before it / leaves the NEST / to the bird

4. a special register / released / a detailed record / and / is kept in / is / the bird / then

5. extensively employed / the method / of / has been / ringing birds / factual data t in recent years / in ., Europe and America / for collecting.

ANSWERS-

1. Migration is one of the greatest mysteries of bird life.

2. Most of the information on migration has come from ringing young and adult birds.

3. A light aluminium ring stamped with a number and return address is fastened to the bird before it leaves the nest.

4. A detailed record is kept in a special register and then the bird is released.

5. In Europe and America, the method of ringing birds has been extensively employed in recent years for collecting factual data.