先热身后鸣禽会唱得更好

热身后鸣禽会唱得更好

Just like an opera singer or pop star would never enter the stage or recording studio without stretching their vocal cords, songbirds appear to practice their singing early in the morning before they put on a full performance a little later on, a new study finds.

一项新的研究发现，就像歌剧演唱家或流行歌手在进入舞台或录音室之前必须伸展他们的声带一样，鸣禽似乎在清晨练习它们的歌唱，然后再在稍晚的时候进行完整的表演。

The research was published in the journal Animal Behaviour.

这项研究发表在《动物行为》杂志上。

Scientists have always been curious as to why birds sing so vigorously and so loudly so early in the morning.

科学家们一直很好奇为什么鸟儿在清晨那么有力、那么大声地唱歌。

“A bunch of reasons have been proposed as to why birds sing most intensely during the dawn chorus,” first author Jason Dinh, a biology PhD student who did the study while an undergraduate at Duke University, told Treehugger. “For example, the temperature might be best for sound transmission, the efficacy of foraging might be low at dawn so birds might invest in other activities like singing, or the rate of territory intrusion is highest at dawn so birds need to sing more to defend their territory.”

该研究的第一作者贾森•丁在接受《拥抱树》采访时表示:“关于鸟类为何在黎明时分唱腔最为强烈，人们提出了很多理由。”他是杜克大学的一名生物学博士，同时也是这项研究的本科生。“例如，温度可能最适合声音传播，黎明时觅食的效率可能较低，所以鸟儿可能会投入到唱歌等其他活动中，或者在黎明时入侵领地的比率最高，所以鸟儿需要更多地唱歌来保护它们的领地。”

The swamp sparrow has a simple song of up to five notes that it repeats 5 to 10 times a second. mirceax / Getty Images

But researchers at Duke were interested in a “warm-up hypothesis” that the intense pre-dawn trilling puts them in best form for singing later in the morning.

但杜克大学的研究人员对一种“热身假说”很感兴趣，即黎明前强烈的颤音能使它们处于最佳状态，适合在早上晚些时候唱歌。

“I think warming up might be one explanation to the dawn chorus, but it is certainly not the only explanation! There are probably several benefits driving birds to sing so intensely at dawn,” Dinh said.

“我认为热身可能是黎明合唱的一种解释，但肯定不是唯一的解释!”让鸟儿在黎明时如此兴奋地唱歌可能有几个好处。”

To test the warming-up theory, researchers recorded 11 male swamp sparrows for several mornings each between 2 a.m. and noon. The swamp sparrow’s song is a simple trill of just five notes or fewer. It repeats five to 10 times a second and sounds a bit “like a melodious police whistle,” co-author Stephen Nowicki, a biology professor at Duke, said in a statement.

为了验证热身理论，研究人员记录了11只雄性沼泽麻雀在早上2点到中午之间的活动。沼泽麻雀的歌声是一种简单的颤音，只有五个音符或更少。杜克大学生物学教授、合著者斯蒂芬·诺维奇在一份声明中说，这种声音每秒重复5到10次，听起来有点“像悠扬的警察哨声”。

Practice Makes Perfect

熟能生巧

The researchers measured each bird’s trill rate and vocal range throughout the mornings. Although swamp sparrows can start singing as early as 2:30 a.m., they aren’t in their best voice as soon as they open their beaks, researchers found.

研究人员测量了每只鸟在早晨的颤音频率和声音范围。研究人员发现，尽管沼泽麻雀早在凌晨2:30就能开始唱歌，但它们一张开嘴并无法发出最好的声音。

Recording analysis showed that the birds start off singing slower or with limited range. They practice hundreds of times, gradually picking up tempo and reaching higher and lower pitch until they perfect their songs right after dawn. The more they practice, the better they sound.

录音分析显示，这些鸟开始时的鸣叫速度较慢或范围有限。他们练习了数百次，逐渐加快节奏，提高和降低音调，直到他们的歌曲在黎明之后变得完美。他们练习得越多，听起来就越好。

“They’re able to perform more difficult songs later in the morning,” Dinh said.

“他们可以在早上晚些时候演奏更困难的歌曲，”Dinh说。

It’s difficult to directly compare birds to humans, said Dinh, but warming up may help birds get their blood flowing and help their temperature increase so their bodies are prepared for the physiological demands of singing.

Dinh说，很难直接将鸟类和人类进行比较，但是热身可以帮助鸟类血液流动，帮助它们提高体温，这样它们的身体就可以为歌唱的生理需求做好准备。

“It is physically challenging to sing high performance songs,” Dinh explained. But the payoff may come in romantic and defensive ways.

“唱高质量的歌曲对身体是一项挑战，”Dinh解释说。但回报可能是浪漫和防御的方式。

“In swamp sparrows, we know that females are more attracted to high performance songs. Furthermore, high performance songs are more threatening to rival males."

“我们知道，在沼泽麻雀中，雌鸟更喜欢高效的歌声。此外，高表现力的歌曲对雄性竞争对手更具威胁性。”