据贾森·G·戈德曼（Jason G. Goldman）报道，人工饲养的极度濒危鸟类状态良好，也就是说它们应已准备好回归自然，独立生活了。

撰文\播音：贾森·G·戈德曼（Jason G. Goldman）

翻译：杨枭

审校：丁可含

Once upon a time, on the big island of Hawaii, it would not have been unusual to hear: 

曾经一度，在夏威夷的大岛上，这种声音很难被听到：

[wild Hawaiian crow call]

[野生夏威夷乌鸦叫声]

That’s the call of the Hawaiian crow. It’s is a critically endangered species, now extinct in the wild after decades of habitat loss, persecution by farmers, and invasive diseases. In the mid-1990s, wildlife biologists rounded up the few surviving crows and put them into a captive breeding program. Today, Hawaiians can once again hear the calls of more than one hundred Hawaiian crows – or 'alalā, as it is called there – but only in aviaries. 

这就是夏威夷乌鸦的叫声。它是一个极度濒危的物种，在几十年里，由于栖息地减少、农业活动影响和疾病的蔓延，野生物种近乎灭绝。在20世纪90年代中期，野生动物生物学家围捕了少数幸存的乌鸦，并将其纳入圈养繁殖计划。今天，夏威夷人可以再次听到超过一百只鸟舍内的夏威夷乌鸦的叫声，当地人称这种乌鸦为'alalā。

[aviary crow call]

[鸟舍乌鸦叫声]

Researchers once focused their efforts primarily on breeding and husbandry. But now they need to know more. 

之前，研究人员主要关注育种和饲养。但现在他们需要了解更多。

"And now that they are doing so well, and it's at the point where they could be in the wild again, now we can look at their vocalizations and their behaviors and things like that." 

“现在乌鸦生活的很好，是时候让它们重归自然，以便我们能够观察它们的叫声、行为等等。”

University of Hawaii bioacoustics researcher Ann Tanimoto. Those other aspects—culture, if you will—are critical for a species as socially complex as the 'alalā.

夏威夷大学生物声学研究员Ann Tanimoto。对于像'alalā这样社群关系复杂的物种来说，你还要考虑文化等方面的影响。

Tanimoto and her team made recordings of captive-bred 'alalā pairs at the Keauhou Bird Conservation Center in Volcano, Hawaii, and compared them to recordings made in the early 1990s by Fish and Wildlife service biologists of the last few wild pairs.

在夏威夷火山的Keauhou鸟类保护中心，Tanimoto和她的团队记录了几对乌鸦的习性，并将它们与1990年代初期的几对进行比较，后者的数据由鱼与野生动物服务站的生物学家记录。

"The wild have more, almost double the number of alarm calls, than the aviary 'alalā do. And they also have these really cool territorial broadcast calls they do in the wild that weren't found in captivity."

“相比于鸟舍，鸟鸣更多见于野外，用于警告的叫声几乎会多一倍。还会有非常酷的用于宣扬领地的叫声，这在鸟舍中是听不到的。”

The absence of the territorial call in captivity makes good sense, because captive birds have different territory demands that wild ones. It also makes sense that they would have fewer alarm calls, because captive birds don't experience the threat of predation. The study was published in the journal Animal Behaviour. [Ann M. Tanimoto et al.. Changes in vocal repertoire of the Hawaiian crow, Corvus hawaiiensis, from past wild to current captive populations.]

因为圈养与野生鸟类对于领土要求不同，所以笼中鸟不会发出领土宣扬的叫声。圈养的鸟也不会受到捕食者的威胁，因此也很少有警报叫声。这项研究发表在期刊《动物·行为》上。

"So we think that their vocalizations that are similar, aviary and wild, are more innate, so basically naturally inside of them. And those that differ are socially learned by being passed on generation to generation."

“野生和圈养的乌鸦的叫声相近，所以我们认为这应该是天生的。那些不同的地方是后天社会习得并代代相传的。”

So what happens when the captive-bred birds are released? They won't have the luxury of learning these calls from their ancestors.

所以，当笼中鸟被放回自然，会发生什么呢？它们不会享有从祖先学习这些叫声的乐趣。

"It will definitely be interesting to determine if they will begin vocalizing something similar to those that they used in the wild before, or if they will begin vocalizing call types that are completely different than those that were in the wild previously."

“这一定很有趣——去决定它们发出过去在野外使用的叫声还是与之前完全不同的声音。”

In Hawaiian mythology, the 'alalā are thought to lead souls to their final resting place near the Ka Lae volcano. With luck, scientists can help the rare species avoid their own journey to Ka Lae.

在夏威夷神话中，'alalā引领灵魂走向最后安息的Ka Lae火山旁。幸亏有科学家，这稀有的物种将避免自己踏上Ka Lae归路。