Hardman Samuel I, Zollinger Sue Anne, Koselj Klemen, Leitner Stefan, Marshall Rupert C, Brumm Henrik
The Institute of Biological, Environmental and Rural Sciences, Aqutic, Behavioural & Evolutionary Biology Group, Aberystwyth University, Aberystwyth SY23 3DA, UK
Communication and Social Behaviour Group, Max Planck Institute for Ornithology, 82319 Seewiesen, Germany.
J Exp Biol. 2017 Mar 15;220(Pt 6):1065-1071. doi: 10.1242/jeb.148734. Epub 2017 Jan 17.
Animals that use vocal signals to communicate often compensate for interference and masking from background noise by raising the amplitude of their vocalisations. This response has been termed the Lombard effect. However, despite more than a century of research, little is known how quickly animals can adjust the amplitude of their vocalisations after the onset of noise. The ability to respond quickly to increases in noise levels would allow animals to avoid signal masking and ensure their calls continue to be heard, even if they are interrupted by sudden bursts of high-amplitude noise. We tested how quickly singing male canaries () exhibit the Lombard effect by exposing them to short playbacks of white noise and measuring the speed of their responses. We show that canaries exhibit the Lombard effect in as little as 300 ms after the onset of noise and are also able to increase the amplitude of their songs mid-song and mid-phrase without pausing. Our results demonstrate high vocal plasticity in this species and suggest that birds are able to adjust the amplitude of their vocalisations very rapidly to ensure they can still be heard even during sudden changes in background noise levels.
利用声音信号进行交流的动物通常会通过提高发声的振幅来补偿背景噪声的干扰和掩蔽。这种反应被称为伦巴德效应。然而，尽管经过了一个多世纪的研究，对于动物在噪声出现后多快能够调整发声振幅却知之甚少。快速应对噪声水平增加的能力将使动物能够避免信号被掩蔽，并确保它们的叫声能够被听到，即使它们被突然出现的高振幅噪声打断。我们通过让雄性歌唱金丝雀暴露于白噪声的短回放并测量它们的反应速度，来测试它们多快能表现出伦巴德效应。我们发现，金丝雀在噪声出现后短短300毫秒内就会表现出伦巴德效应，并且还能够在歌曲中间和乐句中间增加歌声的振幅而不停顿。我们的结果证明了该物种具有高度的发声可塑性，并表明鸟类能够非常迅速地调整发声的振幅，以确保即使在背景噪声水平突然变化时它们仍然能够被听到。
