The birds are arriving in the Arctic up to 13 days earlier than they used to. But at a cost: hunger.

这些鸟比过去提前了13天到达北极，为此付出的代价是：饥饿。

撰文播音：安妮·斯尼德（Annie Sneed）

翻译：张朵儿

Every spring, a bird called the barnacle goose migrates from the coast of the North Sea to the Russian Arctic, where it breeds. That’s a 3000-kilometer trip. Along the way, the geese usually take pit stops to rest and refuel.  But the Arctic spring has been arriving earlier and earlier.

每年春天，一种名叫白颊黑雁的鸟会从北海沿岸迁徙到俄罗斯北部北极圈以内的地区，并在那里繁殖。这是一场长达3000公里的旅程。一路上，它们通常会中途休息和补充能量。但是北极的春天来得越来越早了。

So researchers analyzed six years of barnacle goose migratory tracking data. To try to figure out if these geese—and other species like it—can adapt their migration, to stay in sync with the changing seasons.

研究人员分析了白颊黑雁六年的迁徙追踪数据，试图弄清楚这些鸟类及其他相似物种的迁徙是否与季节变化保持同步。

 “Then we used satellite images to see when snow was melting in the Arctic, and then we could relate the timing of the birds to the snow melt.” Bart Nolet, an ecologist at the University of Amsterdam.

“我们使用卫星图像来观察北极的雪什么时候融化，然后我们可以将鸟类的迁徙期与雪融化的时间联系起来。”阿姆斯特丹大学的生态学家巴特•诺莱特（Bart Nolet）说。

Nolet and his colleagues found that the geese did not leave their wintering grounds sooner to match the earlier Arctic spring. But they did speed up their trip—by skipping many of their usual stopovers. The birds arrived in the Arctic up to 13 days earlier than they used to. But at a cost.

诺莱特和他的同事们发现，黑雁不会提前离开他们过冬地方，来配合北极的早春。但是他们确实会跳过许多以往的停留地点近而加快他们的行程。这些鸟比过去提前了13天到达北极，但这是有代价的。

 “So in a normal year, they start laying their eggs right after arrival. But now they spent more than a week foraging before they laid their eggs…. So in effect, they weren’t that much earlier than would have been the case. As a result, the chicks that hatch from the eggs in that early year, they survive much less than normal. Probably because they missed the food peak, which is a combination of very high quality in the grass, and enough grass around. And that food peak is around three weeks after snow melt, but now they were a few weeks later.”

“在正常的一年中，他们在抵达后会立即开始产卵。但是现在，他们在产卵前花了一个多星期的时间觅食...... 所以实际上，他们的产卵时间并没有比往常早多少。因此，孵化出的幼鸟，存活率远低于正常水平。可能是因为这样孵化出的幼崽错过了草地面积充裕且草质高的食物高峰期。食物高峰期约为雪融化后的三周，但现在孵化出的幼崽时已经迟了食物高峰期几周。”

With devastating effects.

这将带来毁灭性的影响。

 “We looked at the daily survival of the goslings... If you calculate it over the whole month, then it’s quite dramatic, they decrease from 20 percent to only 2 percent surviving. It basically means that not many goslings are surviving in such a year.” The study is in the journal Current Biology. [Thomas K. Lameris et al., Arctic Geese Tune Migration to a Warming Climate but Still Suffer from a Phenological Mismatch]

“我们研究了小雁每日的生存情况......如果你按整个月计算，那么情况非常带有戏剧性，小雁的存活率从20％减少到了只有2％。这意味着在这一年里没有多少小雁存活下来。”这项研究发表在《当代生物学 》杂志上。

So why don’t the geese just leave their wintering grounds earlier?

那么大雁为什么不早点离开他们的越冬地呢？

 “When it’s an early spring in the Arctic, it’s not necessarily an early spring in the wintering area. So the birds cannot use any cue that’s related to what’s early or late spring to leave.”

“当北极进入早春时，越冬地不一定也是早春。因此，鸟类无法得到任何与早春或晚春相关的提示信息。”

But Nolet does think there’s some hope they might be able to adapt. “We know that the goslings learn their migration from their parents, so there’s a lot of learned behavior in it. So it may well be that in the course of time, some birds discover that they have to depart earlier from their wintering areas to be able to time their migration perfectly, and match it with the Arctic.”

但诺莱特仍然对鸟类的适应抱有希望。“我们知道小雁从他们的父母那里学习迁徙，还包括更多的学习行为。因此，随着时间的推移，有些鸟类会发现它们必须早早地离开它们的越冬地才能完美地完成迁徙，从而与北极的变化相适应。”