清晨悅耳的鳥鳴讓人心曠神怡，但是一天中的其他時間卻很少能聽到鳥叫。為什么鳥兒都喜歡在清晨歌唱？來本文中尋找答案吧。

Wake up early enough and, depending on where you live, you’ll likely hear a pleasant chorus of birds chirping their tiny hearts out. This am avian arrangement is instinctual behavior for birds, but why?
早上起得夠早的話，在你所住的地方也許能聽到一陣悅耳的鳥鳴。在清晨歌唱是鳥的本能行為，但是鳥鳴為什么都在清晨呢？

According to the Woodland Trust, this early singing is known as the dawn chorus, and it can start as early as 4 am and last for several hours. Birds do it to attract mates and warn other birds to avoid their turf. One theory as to why they opt for the wee hours to communicate these important messages is because the low visibility makes it hard to do other bird activities, like foraging. Keeping their activity level low, they opt to sing instead.
林地信托機構稱，鳥兒在清晨鳴叫最早從凌晨4點開始，可持續數個小時。鳥鳴叫是為了吸引配偶，也是為了警告其他鳥不要入侵自己的領地。關于鳥類為什么選擇在凌晨傳遞這些重要信息，有一個理論是，凌晨能見度低，鳥類難以進行覓食等其他活動，既然無事可做，那么鳥兒就轉而選擇鳴叫。

Another theory argues that birds use the morning vocals to project an image of strength. By singing with fervor, they’re letting other birds know they survived the night—no guarantee in nature—and would make for an excellent mate.
另一種理論認為，鳥類利用晨鳴來展示自己的力量。通過熱情地歌唱，它們讓其他鳥兒知道自己已經安然度過黑夜——要知道自然界的動物過著朝不保夕的日子，不一定能看見明天的太陽——并能夠成為出色的伴侶。

Like a good recording studio, the early morning hours also allow birds to transmit a clear tune thanks to the cooler, drier air. Because birds have distinctive chirps, that clarity helps them be more easily identified by birds within listening distance.
清晨的空氣更涼爽、更干燥，就像一個效果很好的錄音棚，鳥兒在此時歌唱能傳遞出清晰的音質。因為鳥兒的聲音各有不同，這種清晰度可以讓聽得見的鳥兒更容易識別出它們的聲音。

There used to be a prevailing theory that birds sang so much in the mornings because the sounds could travel greater distances due to less atmospheric turbulence, but it was disproven by researchers at the University of Western Ontario in 2003. They played recordings of sparrows at dawn and midday. The songs didn’t travel farther, but they were more consistent.
過去有一個流行的理論認為，鳥兒最愛在清晨鳴叫是因為在氣流穩定的時候聲音能傳播得更遠。但是西安大略大學的研究人員在2003年否定了這一理論。研究人員在黎明和中午分別播放了麻雀的錄音。然而麻雀聲音并沒有傳播得更遠，只不過黎明時分麻雀的叫聲更連貫。

Because birds only have so much energy to belt one out, singing when they stand the best chance of being heard makes sense. For a bird, an early morning session is like having the perfect acoustic environment for their performance.
因為鳥兒只能用有限的精力來鳴叫，它們自然會選擇在最可能被聽到的時候歌唱。對一只鳥兒來說，清晨鳴叫相當于在最佳音效環境中表演。

英文來源：Mental Floss

編譯：丹妮

審校：董靜、齊磊