How Do Birds Find Their Way

How Do Birds Find Their Way

鸟类如何辨别方向

We can watch birds fly from tree to tree, from tree to house, then back again. They seem to fly here, and there, and anywhere.

你看，鸟儿到处飞，它从这棵树飞到那棵树,从树上飞到房子上,来来回回

If we watch birds all year, we find that some seem to disappear in fall, when the days get shorter and colder. They are flying south, where it is warmer.

如果我们整年都观察，就会发现,当秋季来,白天越来越短，天气越来越凉,有些鸟看不见了。原来，它们飞到温暖的南方去了。

Early in spring the first birds begin to come back. Every spring birds return north to make their nests, lay eggs, and hatch their babies. We say the birds are“ migrating. ” They are moving from their winter homes in the south to their summer homes in the north. Once they reach their northern homes, they will build their nests. They may build nests in trees or shrubs, or on porch ledges. Or, like the woodpeckers, they may bore holes down into trees and make their cozy nests inside. Some go to the same nesting area or even the exact same nest that they used the summer before.

早春,第一批鸟陆续飞回来了。每到春天,它们都要回到北方,筑巢、下蛋和孵化幼鸟我们说鸟在迁徙,它们从南方过冬的家,迁到北方的家过夏天。 鸟回到北方的家园,立刻开始筑巢,可能在树上、灌木丛或屋檐下。比如,啄木鸟会凿洞,在树洞里筑一个温暖的巢。有些鸟在上个夏天同样的地方筑巢,甚至就住在以前的巢中。

Long ago people did not know that some birds migrate. They thought the birds hid in holes in the ground and slept all winter. Some people guessed that birds spent the winter in the mud on the bottoms of ponds. Now we know where these birds go. When birds start to migrate, ornithologists-scientists who study birds-use trap sand nets to catch a few of them. They put bands on their legs and then let the birds go. The bands do not hurt the birds. Each band has a code on it that tells where and when the bird was banded.

很久以前,人们不知道有些鸟会迁徙。他们认为,整个冬天鸟一直躲在地洞里睡觉;也有人猜想，鸟在池塘底下的稀泥中过冬。 现在,我们知道这些鸟去哪儿了。鸟开始迁徙时,鸟类学家(研究鸟的科学家)用夹子或者网捕捉一些鸟,给它们戴上标记环,然后放飞。这些标记环不会伤害鸟,上面刻着代码记录了每只鸟戴标记环的时间和地点。

Some birds migrate for weeks because they stop along the way. Other birds fly for only a few days. Some birds fly thousands of miles when they migrate. We know that orioles fly south to Panama. And barn swallows fly to Central and South America. Hummingbirds weigh only as much as a penny, yet they fly over water for 500 miles, without stopping, when they migrate. Arctic terns fly more than 10, 000 miles-all the way from Northern Maine to the South Pole. But how do the birds know where to go? And how do they find their way? That's the big mystery.

有的鸟会在途中停留,因此迁徙要花几个星期。有的鸟只需几天。有的鸟迁徙长达数千公里。橙腹拟黄鹂往南飞到巴拿马,北美洲的家燕则要飞到中南美洲。 蜂鸟只有一枚硬币重,但在迁徙的时候,能飞过八百里海洋,无需停下来休息。北极燕鸥要飞越一万多公里,从美国缅因州北部一直到南极。鸟类怎么知道要去哪儿?它们又如何辨识方向呢?这成了一个巨大的谜团。