【已调整句子】这个木刻版显示的是16世纪的渔夫把冬眠的一大群Netload 燕子从结冰的湖面拉上来的画面。
This 16th century woodblock shows fisherman pulling a big netload of hibernating swallows
如果你还没有听说过有燕子在冬天冬眠在湖泊的湖底这故事。（没关系～）
from a frozen-over lake. If you haven’t heard about how swallows hibernate through the winter
那是因为古时候的他们不知道真相。
at the bottom of lakes, it’s because they don’t. But, for thousands of years, hibernation
但是几千年来，冬眠是用来来解释鸟儿在秋天和春天之间去了哪里的主要理论
was one of the leading theories to explain where birds went between fall and spring.
另一种理论是,鸟儿在冬天全部都离开,飞到很远很远的地方,我们叫做迁徙
Another theory was that the birds left entirely and flew far away for the winter — we call
但是鸟儿会去哪里了，他们没有一个线索。
this "migration" — but they didn’t have a clue where the birds would go. For example,
比如，一本1703年的小册子写道，鸟儿们已经去了月球。
a pamphlet from 1703 suggested that they went to the moon.
第一个真正的关于冬季候鸟会了去哪里的线索,
The first real clues about where migratory birds actually go during the winter — hint:
提示：不是在月亮或冻湖的底部,大约在1900年,由于丹麦人
it’s not the moon or the bottom of a frozen lake — came around 1900, thanks to a Danish
老师的附加技术标志着铝环鸟的腿,然后重新放生鸟儿们
teacher’s technique of attaching marked aluminum rings to birds’ legs and then re-releasing
每次捕获或看带铝环的鸟，就在地图上画一个点,很快,
them. Each recapture or sighting of a banded bird put a dot on the map, and soon, long-distance
长距离地迁徙证实当白鹳已经纠集在匈牙利，当被发现时已经死在南非。
earthly migrations were confirmed when a White stork that had been banded in Hungary was
但是条带只能告诉研究人员沿着一条候鸟的迁徙路径。
found dead in South Africa. But banding can only tell researchers about single points
不能知道在点与点之间候鸟们发生了什么事情。
along a bird’s migratory path — not what happens BETWEEN those points.
最近,研究人员终于开始得到更好的视图,鸟瞰，
More recently, researchers finally started to get a better view — a bird’s-eye view,
事实上,这些年度迁徙,当一个秃鹰在马里兰州和被捕
in fact — of these annual migrations, when a bald eagle in Maryland was captured and
配备了一个发射机强大到足以给一双绕轨道运行的卫星发出的信号。
fitted with a transmitter powerful enough to send signals to a pair of orbiting satellites.
卫星跟踪透露了一些显著的迁移的细节,比如（斑尾鹬）
Satellite tracking revealed details of some remarkable migrations, like the bar-tailed
黑尾豫的年度飞行从阿拉斯加到新西兰,在鸟占地11000千米
godwit’s annual flight from Alaska to New Zealand, during which the bird covers 11,000
大约八天没有停下来一次。但是有一个严重的限制,卫星
km in about eight days without a single stop. But there’s a serious limitation to satellite
的跟踪装置:即使现代科技,信号发射器有足够的能量来发射信号
tracking devices: even with modern technology, transmitters with enough oomph to send signals
对于小型鸣禽，卫星发射器仍然过于沉重。
to satellites are still far too heavy for small songbirds.
有了小小的进步是使用GPS记录器,可以更小,因为它们是接收的而不是发送信号给卫星的。
A slight improvement is to use gps recorders, which can be smaller because they receive
,但对于最小的鸟类来说他们仍然太重。
rather than send signals to satellites — but they’re still too heavy for the smallest birds.
幸运的是,科学家们已经够聪明,意识到他们不需要所有卫星跟踪了。
Luckily, scientists have been clever enough to realize they don’t need satellite tracking
取而代之，我们可以给鸟儿安装一个很小的光级地理定位器，时钟和内存芯片，
at all! Instead, we can fit birds with a tiny light-level recorder, clock, and memory chip,
其重仅达一粒葡萄干。轻量级非转播光记录仪
which together weigh as much as a raisin. Lightweight light-recorders don’t broadcast
所以我们需要重新获取鸟儿的数据,但是我们可以使用古老的导航的
so we need to recapture the birds to get the data, but we can then use ancient navigation
方法来重建鸟儿们在迁徙途中每天的位置:
methods to reconstruct the bird’s daily location over the course of its journey: the length
纬度的长度每一天都是一个指标,介于日落和日出
of each day is an indicator of latitude, and the time halfway between sunset and sunrise
(中午)是一个经度的指示器。
(that is, noon) is an indicator of longitude.
用这些巧妙的方法进行阐明迁徙:世界飞行速度最快的鹬
These clever geolocators have shed light on the world’s speediest migration: the Great
,重约170克(半罐汽水),长尾鹬他从瑞典
snipe, which weighs about 170 grams (half a can of soda-pop), high-tails it from Sweden
到达中非要短短三天,其平均每小时95公里。
to Central Africa in just three days, averaging 95 km per hour.
另一个马拉松候鸟,北极燕鸥,长期以来一直认为,最长的迁徙
Another marathon migrator, the Arctic tern, has long been credited with the longest migration
在北极和南极之间的往返飞行，每年估计旅程为40 000公里
for its annual round-trip flight between the Arctic and Antarctic—an estimated 40,000
但是最近光级地理定位器的数据显示,燕鸥实际上飞行的路程超过旅行路径的两倍远
km. But recent data from light-level geolocators show that terns actually travel more than
每年可能利用盛行风去迁徙。
twice as far each year, possibly to take advantage of prevailing winds.
这意味着北极燕鸥的一生有着超过2半百万公里的飞行时长。
This means that arctic terns can rack up over 2 and a half million kilometers of flight
足够三个往返月球之间的距离。
in a lifetime — enough for three round trips to the moon. But as far as we know, they haven’t
但是据我们所知，它们不会实际上在那里（月球）。
actually made it there yet.