Why don’t birds get lost on their l

Why don’t birds get lost on their long migratory flights? Scientists have puzzled over this question for many years. Now they’re beginning to fill in the blanks.
Not long ago, experiments showed that birds rely on the sun to guide them during day¬light hours. But what about birds that fly mainly by night? Tests with artificial stars have proved conclusively that certain night-flying birds are able to follow the stars in their long-distance flights.
One such bird—a warbler (鸣禽)—had spent its lifetime in a cage and had never flown under a natural sky. Yet it showed an inborn ability to use the stars for guidance. The bird’s cage was placed under an artificial star-filled sky at migration time. The bird tried to fly in the same direction as that taken by his outdoor cousins. Any change in the position of the make-believe stars caused a change in the direction of his flight,
Scientists think that warblers, when flying in dayflight, use the sun for guidance. But the stars are apparently their chief means of direction-finding. What do they do when the stars are hidden by clouds? Apparently they find their way by such landmarks as mountain ranges, coast line, and river courses. But when it’s too dark to see these, the warblers circle helplessly, unable to get their directions.

結果 (中文) 1:

为什么不迷路鸟在他们长期以来迁徙飞行?科学家们一直困扰的问题这个问题很多年了。现在他们开始来填空。不久前，实验结果表明，鸟类依靠太阳，引导他们在 day¬light 小时。但是主要夜间飞行的鸟呢?测试用人工星星已经最终证明某些夜间飞行的鸟类都能够按照自己的长途飞行中的星星。这样一只鸟 — — 莺 (鸣禽) — — 在一个笼子里度过其生命周期和天然的天空下永远不会飞。但是它依然有与生俱来的能力，利用星星为指导。在鸟的笼是人工的布满星星的天空下置于迁移时间。那只鸟想飞在户外兄弟采取相同的方向。在虚幻的星星的位置任何变化导致改变飞行方向的他，科学家认为，莺，在 dayflight，飞行时用于指导的太阳。但是明星显然是测其主要手段。当星星被云层遮盖的时候，他们会做什么?显然他们找到路的山脉、 海岸线，以及河道等地标建筑。但当它是太黑了，看到这些，莺圈无助，无法得到他们的方向。

結果 (中文) 3:

为什么小鸟不会在漫长的迁徙飞行中迷失？科学家们对这个问题困惑了很多年。他们现在开始填补空白。
不久前，实验表明，鸟类依靠太阳来指导他们一天¬光时。但那些粉主要由夜鸟？人造星星做的试验证明某些夜间飞行的鸟类能跟随星在他们的长途飞行。
一雀莺（鸣禽）-一生待在笼子里，从来没有在自然的天空下飞行。然而，这表明利用星星导航的一种天生的能力。鸟的笼子放在人造星空下的迁移时间。鸟要飞在同一方向，采取了户外堂兄弟。在虚幻的星星引起改变其飞行方向的位置的任何变化，
科学家认为莺，在天飞行时，利用阳光的指导。但是星星显然是他们主要的测向方法。他们做什么，当星星被乌云？显然，他们发现他们的方式通过山脉，海岸线和河流等地标性建筑。但当它太黑暗看到这些，莺圈无奈，无法得到他们的方向。