科学美国人60秒 SSS 奇鸟迁徙两次繁殖后代（在线收听）

This is Scientific American's 60-second Science, I'm Susanne Bard.

这里是科学美国人——60秒科学系列，我是苏珊娜·巴德。

Most migratory birds spend their winters in one habitat and then fly to a new area in the springtime to breed. They'll raise one or more broods of young there. Then, come fall, they begin the trip back to their wintering grounds.

大多数候鸟在一个栖息地过冬，然后在春天飞往另一个地方繁殖。它们会在那里养育至少一窝幼鸟。然后，在秋天来临时，它们会开始返回越冬地。

But a new study suggests the phainopepla, a jet-black bird with a body type like a small cardinal, may have a different strategy.

但一项新研究表明，体型像小红雀且毛发黑亮的亮丝鶲可能有不同策略。

"They might be itinerant breeders.So they breed once in one area, then they migrate—they go somewhere else, and they breed a second time in that new area."

“它们可能是巡回繁殖者。它们在一个地方繁殖一次，然后迁移到另一个地方，在新地方进行第二次繁殖。”

State University of New York, Oswego, evolutionary biologist Daniel Baldassarre.

纽约州立大学奥斯威戈分校的进化生物学家丹尼尔·巴尔达萨雷说到。

For the phainopepla, that means nesting in the desert Southwest during the springtime before flying to the oak woodlands of the California coast for the summer.

对亮丝鶲来说，这意味着春天在西南沙漠筑巢，然后飞往加利福尼亚海岸的橡树林地过夏天。

Baldassarre says bird-watchers have long suspected that phainopeplas are itinerant breeders. One hint that the same birds might be breeding in two different habitats was their vocal behavior. The pointy-headed songbirds are talented mimics, often copying the vocalizations of other bird species.

巴尔达萨雷表示，鸟类观察者一直怀疑亮丝鶲是巡回繁殖者。同一种鸟在两个不同栖息地繁殖的其中一个征兆，就是它们的发声行为。这些聪明的鸣鸟是天才模仿者，它们经常模仿其它鸟类的叫声。

（音频剪辑：雌性声音模仿）

(CLIP: Female vocal mimic)

"If you look at desert birds, they actually can mimic some species that you don't find in the desert—bird species that you would only find out in these woodland habitats."

“如果你观察沙漠鸟类，你会发现它们实际上可以模仿在沙漠中找不到的鸟类的叫声，这些鸟类只能在林地栖息地中找到。”

And the reverse is also true: phainopeplas in woodland habitats will mimic species that are only found in the desert.

反之亦然，林地亮丝鹟也会模仿只在沙漠里才能找到的鸟类的叫声。

But to confirm that individual phainopeplas really do spend the breeding season in two different places, Baldassarre and his team outfitted the birds with tiny GPS transmitters and tracked their movements.

但为了确认个体亮丝鹟确实会在两个不同地方度过繁殖季，巴尔达萨雷及其团队给这些鸟装上了微型GPS发射器，并追踪它们的活动。

"They all left those desert breeding habitats, migrated out to these coastal woodland habitats and stayed in a small kind of territory for basically the duration of summer, when we know that phainopeplas are breeding in these woodland areas."

“它们都离开了沙漠繁殖地，迁移到这些沿海林地栖息地，在一小块领地上度过了几乎整个夏天，而我们知道亮丝鹟夏天在这些林地繁殖。”

The researchers also found that both populations were very similar genetically, suggesting that they're all members of the same gene pool.

研究人员还发现，这两个群体在基因上非常相似，这表明它们属于同一个基因库。

The study appears in the journal the Auk.

这项研究发表在《海雀》期刊上。

Baldassarre says itinerant breeding has only been documented in two other bird species to date and is most likely an adaptation to unpredictable sources of food.

巴尔达萨雷表示，迄今为止，只有另外两种鸟类有巡回繁殖记录，这种行为很可能是为了适应不可预测的食物来源。

"That food supply disappears, and so the birds literally have to physically move to follow the food."

“食物供应消失了，所以这些鸟不得不追随食物移动。”

Such behavioral flexibility seems to be unusual, Baldassarre notes. Phainopeplas could thus be especially resilient in the face of climate change—a challenge other species may not be able to meet.

巴尔达萨雷指出，这种行为上的灵活性似乎不同寻常。因此，亮丝鹟可能会特别适应气候变化——而这是其它物种可能无法应对的挑战。

Thanks for listening for Scientific American's 60-second Science. I'm Susanne Bard.

谢谢大家收听科学美国人——60秒科学。我是苏珊娜·巴德。