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Wild Songbirds Can Pick Up New Tunes¹

Only a few kinds of animals are known to learn their vocalizations from listening to others. Us, of course. Elephants. Bats. Cetaceans—whales and dolphins. Pinnipeds—walruses, seals and sea lions. And parrots, hummingbirds³ and songbirds. That's it. "When your cat meows or your dog barks, it does that because it has genetically⁴ inherited that sound. But birds are like us, young animals have to hear adults in order to develop normal sounds."University of Windsor biologist Daniel Mennill.

只有少数几种动物通过倾听别人的声音来学习发声。当然,我们的大象、蝙蝠、海豚、鳍脚类如海象、海豹和海狮。还有鹦鹉、蜂鸟和鸣禽。就是这样。“当你的猫叫或狗叫时，它会这样做，因为它遗传了这种声音。”但是鸟类和我们一样，幼兽为了发出正常的声音，必须听到成年的声音。温莎大学的生物学家Daniel Mennill说。

There have been hundreds of conventional experiments done in laboratories with captive birds that support the idea that young birds learn to sing by listening to older birds. These studies also taught us that birds, like humans, have what's called a "sensitive period" early in life, a time when they are most disposed to learn how to vocalize from their elders.But nobody ever did one of those experiments with wild birds. Observational studies, yes. But no true experiments. Until now, thanks to some wild savannah sparrows.

在实验室里进行的数百项传统实验，都是用圈养的鸟类做的，这些实验支持了一个观点，即幼鸟通过听老鸟唱歌来学习唱歌。这些研究还告诉我们，鸟类和人类一样，在生命早期也有一段被称为“敏感时期”的时期，在这个时期，它们最倾向于学习如何从长辈那里发声。但是从来没有人用野生鸟类做过这样的实验。观察性研究,是的。但没有真正的实验。直到现在，多亏了一些野生的草原麻雀。

"So this population of savannah sparrows lives on an island in the Bay of Fundy in eastern North America, and it's been studied since the 1960s, so we know a lot about this population. It means we know every kind of sound that has ever been uttered by a savannah sparrow in this population over the course of many decades."Mennill and his team installed a series of loudspeakers on the island, and they played new tunes that the sparrows would never have heard otherwise.

“萨凡纳麻雀的种群生活在北美东部芬迪湾的一个岛上，从20世纪60年代就开始研究了，所以我们对这一种群有了很多了解。”这意味着我们知道几十年来草原麻雀发出的每一种声音。Daniel Mennill和他的团队在岛上安装了一系列扬声器，播放着麻雀们听不到的新歌。

"The kinds of sounds that we broadcast to the animals were based on savannah sparrows, the same species, but recordings⁵ collected on the western coast of North America, many thousands of miles away from our study population."For six years, the researchers broadcast these novel songs to five cohorts of sparrows. "Lo and behold⁶, this bird that arrived to breed in the spring of 2014 opened his beak⁷ and sang a song that was a perfect match with one of our stimuli⁸."

“我们向这些动物播放的声音，都是基于草原麻雀的声音，但这些声音都是在北美西海岸收集的，距离我们的研究对象有几千英里远。”在六年的时间里，研究人员将这些新奇的歌曲广播给五组麻雀。“你瞧，这只在2014年春天来到这里繁殖的鸟张开嘴，唱出了一首与我们的刺激完全匹配的歌。”

In all, 26 birds learned their songs from loudspeakers rather than from other birds. And they had the same survival and reproductive success as all the other birds. All but one successfully mated and defended their territories. And four additional birds learned songs from birds that had originally learned from the loudspeakers.

总共有26只鸟是通过扬声器，而不是其他鸟类来学习鸣叫的。它们的生存和繁殖成功率和其他鸟类一样。除一人外，所有人都成功交配并保卫了他们的领土。另外4只鸟从原先从扬声器里听到的鸟儿那里学来了歌曲。

"What we have now is a very unique, maybe a globally unique population of animals, where some of the animals sing population typical songs, that sound like other animals in their breeding population. But our experimental subjects who are living there now, are singing songs that are slightly different." By returning to the island year after year, Mennill can study not only vocal² learning, but the transmission of culture from one generation to the next. There’s a lot going on in those bird brains.

“我们现在拥有的是一种非常独特的动物，也许是一种全球独特的动物种群，一些动物会唱一些典型的歌曲，听起来就像它们繁殖种群中的其他动物一样。”但是我们的实验对象现在住在那里，他们唱的歌有点不同。年复一年地回到岛上，Mennill不仅可以学习声乐，还可以学习文化的代代相传。这些鸟的大脑里有很多东西。