A new study from Lund University in Sweden shows that the presence or absence of moonlight has a considerable effect on when migratory (迁徙的) birds take flight in the autumn.
Together with his colleagues, Gabriel Norevik studied European nightjars (夜莺) and how the lunar cycle and moonlight affect the leaving time when the birds start their three-month-long migration flight to areas south of the Sahara.
Using miniature (微型) data loggers the researchers recorded the activity of 39 European nightjars over a one-year period. The result shows that the birds begin their autumn migration south about ten days after the full moon, and that the individual birds synchronise (同速进行) the migration and fly off more or less at the same time. “It surprised us that the lunar cycle and the time the birds spent in hunting insects covary so well. This in turn affects their migration pattern in such a way that they synchronise their flight so that almost all of them fly off at the same time ten days after the full moon,” says Gabriel Norevik. European nightjars use their sight when they hunt at night. In the moonlight they find it easier to catch flying insects and refill their energy reserves.
The birds migrate in three stages from northern European to wintering sites south of the Sahara. Each stage follows the same pattern: first the moon provides double of the light for the birds to hunt insects, and the next stage of the migration starts ten days after the full moon.
The researchers doubt whether other birds also adapt to the lunar cycle when they migrate. “We will go on to examine that and what effects this type of synchronised migration has on the birds themselves and their surroundings,” says Gabriel Norevik.
【小题1】What can we learn from paragraph 3?| A．39 European nightjars were charted over a lifelong period. |
| B．European nightjars catch flying insects more easily by means of moonlight. |
| C．The individual birds start the migration ten days later than group birds. |
| D．The lunar cycle and the ending of the birds migration covary very well. |
| A．The birds’ migration has three patterns. |
| B．The birds migrate to northern Europe for food. |
| C．The stage of the migration starts after the full moon. |
| D．European nightjars’ migration is from August to December. |
| A．Nightjars’ habitat. | B．Absence of the moon. |
| C．Other birds’ migration. | D．Insects’ surroundings. |
| A．Migration Flight and moonlight | B．Migratory Birds and Autumn |
| C．Ten Days Makes a difference | D．European Nightjars Need to Migrate |
