Back in 2010, an international research team fitted tracking devices to birds they believed to be special – Arctic terns. And it turns out they were right, as described in US journal, PNAS. The Arctic tern has an extraordinary year-long migration from the Arctic Circle to the Antarctic Circle and back again.

早在 2010 年，一个国际研究团队就为他们认为很特别的鸟类——北极燕鸥安装了跟踪装置。事实证明他们是对的，正如美国期刊《美国国家科学院院刊》所描述的那样。北极燕鸥经历了长达一年的从北极圈到南极圈再返回的非同寻常的迁徙。

What does this route look like? Arctic terns begin their migration in the Northern hemisphere in the summer, which is breeding season. As it gets colder and darker, turning to winter, the birds fly southward, parallel to the coast of South America or hugging the coast of the African continent to reach their winter feeding ground, the Antarctic Circle. And they do not always fly in a straight line. While heading back up north, their flight path mimics an S-shape which they follow to save energy while navigating the wind systems in the different hemispheres. This journey is a round-trip of up to 35,000km long, which makes the Arctic tern's migration the longest of any bird. Plus, they see more daylight than any other animal on Earth!

这条路线是什么样的？北极燕鸥在夏季即繁殖季节开始在北半球迁徙。随着天气越来越冷，越来越黑，转入冬季，鸟类向南飞去，平行于南美洲海岸或紧贴非洲大陆海岸，到达它们越冬的觅食地——南极圈。而且它们并不总是直线飞行。在向北返回时，它们的飞行路径模仿 S 形，它们遵循该形状以节省能源，同时在不同半球的风力系统中航行。这段旅程往返长达 35,000 公里，这使北极燕鸥的迁徙成为所有鸟类中最长的一次。此外，它们比地球上任何其他动物都能看到更多的日光！

But, on this epic journey, the birds do take some well-deserved breaks. Heading northward, the population stops on the north and west coast of the UK to breed. A female lays one to three eggs in a nest, and after an incubation period of around three weeks, they hatch, and fluffy brown and grey chicks emerge. Meanwhile, the adult birds feed in the shallow coastal waters on fish, such as sand-eels. In contrast, while heading south, the birds appear to stop off in the middle of the North Atlantic Ocean, where they indulge on fish and zooplankton, preparing themselves for their long journey ahead.

但是，在这段史诗般的旅程中，鸟类确实得到了一些当之无愧的休息。向北前进，人口在英国的北部和西海岸停止繁殖。一只雌性在一个巢中产下一到三个卵，经过大约三周的孵化期后，它们孵化，并出现毛茸茸的棕色和灰色小鸡。与此同时，成年鸟类在沿海浅水区捕食沙鳗等鱼类。相比之下，当向南飞行时，这些鸟类似乎会停在北大西洋中部，在那里它们沉迷于鱼类和浮游动物，为接下来的漫长旅程做好准备。

So, if you ever see a little black and white bird with red legs and a red beak, show them some appreciation. They have flown a long way to see you!

所以，如果您看到一只红腿红嘴的黑白相间的小鸟，请向它们表示感谢。他们飞了很远的路来看你！

词汇表

tracking device 跟踪装置
Arctic tern 北极燕鸥
migration 迁徙
Arctic Circle 北极圈
Antarctic Circle 南极圈
route 路线
Northern hemisphere 北半球
breeding 繁殖
southward 向南地
continent 大陆
feeding ground 觅食地
flight path 飞行路线
wind system 风系
round-trip 往返旅程
lay 产（蛋）
nest 鸟窝，鸟巢
incubation 孵化
hatch （雏鸟）孵出，破壳而出
chick 雏鸟
stop off 中途停留
zooplankton 浮游动物
beak （鸟）嘴，喙