細(xì)尾鷯鶯通過(guò)偷聽(tīng)灌木鷯鶯的叫聲來(lái)躲避猛禽。（圖片提供:Simon Bennett;Robert Magrath）
學(xué)習(xí)一門外語(yǔ)絕對(duì)是個(gè)挑戰(zhàn),，但有時(shí)卻是必須的，對(duì)于澳大利亞細(xì)尾鷯鶯而言更是如此——這種小鳥(niǎo)靠著偷聽(tīng)鄰近鳥(niǎo)類的警報(bào)來(lái)逃脫食雀鷹的利爪,。一項(xiàng)新的研究顯示,，細(xì)尾鷯鶯之所以能夠識(shí)別這些叫聲，并非因?yàn)樗鼈兟?tīng)起來(lái)與自己的叫聲類似,，而是因?yàn)檫@些小鳥(niǎo)已經(jīng)搞清了其中的含義,。
具有警報(bào)性質(zhì)的叫聲是動(dòng)物抵御外敵入侵的第一招，特別是當(dāng)猛禽來(lái)襲時(shí),，那些群居生活的小型鳥(niǎo)類更是會(huì)嘰嘰喳喳叫個(gè)不停,。一些鳥(niǎo)類具有復(fù)雜的叫聲體系，還有一些鳥(niǎo)類在自己鳴叫的同時(shí)還會(huì)聆聽(tīng)其他鳥(niǎo)類的叫聲,。這項(xiàng)研究的第一作者,、澳大利亞堪培拉市國(guó)立大學(xué)的生物學(xué)家Rob Magrath指出，其實(shí)偷聽(tīng)是一個(gè)不錯(cuò)的備份策略,，這是因?yàn)?ldquo;鳥(niǎo)類不再需要……親自看到入侵者”,，同時(shí)能夠有更多的時(shí)間用來(lái)覓食。但是鳥(niǎo)類如何聽(tīng)懂其他鳥(niǎo)類發(fā)出的紅色警報(bào)呢,？
Magrath和他的同事將研究目標(biāo)鎖定在細(xì)尾鷯鶯和灌木鷯鶯上——這是兩種以昆蟲(chóng)為食的澳大利亞小鳥(niǎo),，它們同時(shí)又是猛禽喜愛(ài)的獵物。在這項(xiàng)試驗(yàn)的第一階段,，研究小組錄制了灌木鷯鶯看到假食雀鷹后發(fā)出的警報(bào)叫聲,。隨后，研究人員向生活在兩種不同環(huán)境——堪培拉市（細(xì)尾鷯鶯和灌木鷯鶯混居）和麥克夸利河濕地（僅有細(xì)尾鷯鶯獨(dú)居）——中的細(xì)尾鷯鶯播放了上述錄音,。結(jié)果顯示,，當(dāng)聽(tīng)到灌木鷯鶯的叫聲后，生活在堪培拉的細(xì)尾鷯鶯會(huì)掩護(hù)其他同伴飛走,，而生活在麥克夸利河濕地的細(xì)尾鷯鶯則并不理睬這些叫聲,。
Magrath表示，這些發(fā)現(xiàn)表明,，細(xì)尾鷯鶯已經(jīng)知道灌木鷯鶯的叫聲代表什么含義了,。他解釋說(shuō)，細(xì)尾鷯鶯和灌木鷯鶯的警報(bào)叫聲聽(tīng)起來(lái)非常類似,，因此如果細(xì)尾鷯鶯之所以識(shí)別這些警報(bào)僅僅是因?yàn)樗鼈兟?tīng)起來(lái)很像,，那么生活在麥克夸利河濕地的細(xì)尾鷯鶯也應(yīng)該飛走才對(duì)。研究人員同時(shí)發(fā)現(xiàn),，細(xì)尾鷯鶯還能夠聽(tīng)懂其他一些差異顯著的警報(bào)叫聲,，例如新荷蘭蜜雀——另一種在堪培拉市很常見(jiàn)的小鳥(niǎo)——的叫聲。盡管在程度和頻率上存在明顯差異,，但是當(dāng)研究小組播放新荷蘭蜜雀的紅色警報(bào)時(shí),，細(xì)尾鷯鶯同樣也會(huì)飛走,。研究小組在最近的英國(guó)《皇家學(xué)會(huì)學(xué)報(bào)B》網(wǎng)絡(luò)版上報(bào)告了這一研究成果。
擅長(zhǎng)研究鳥(niǎo)類用聲音傳遞信息的英國(guó)布里斯托爾大學(xué)的生物學(xué)家Andrew Radford認(rèn)為這一發(fā)現(xiàn)非常引人注目,。Radford表示：“這篇論文提供了迄今為止最有力的間接證據(jù),，表明學(xué)習(xí)真的在鳥(niǎo)類如何理解其他物種的警報(bào)中扮演了一個(gè)重要角色。”（生物谷Bioon.com）
生物谷推薦原始出處：
Proceedings of the Royal Society B,，doi:10.1098/rspb.2008.1368，Robert D. Magrath,，Janet L. Gardner
Recognition of other species' aerial alarm calls: speaking the same language or learning another?
Robert D. Magrath1, Benjamin J. Pitcher1, Janet L. Gardner1
1 School of Botany & Zoology, Australian National University, Canberra, Australian Capital Territory 0200, Australia
Alarm calls given by other species potentially provide a network of information about danger, but little is known about the role of acoustic similarity compared with learning in recognition of heterospecific calls. In particular, the aerial ‘hawk’ alarm calls of passerines provide a textbook example of signal design because many species have converged on a design that thwarts eavesdropping by hawks, and call similarity might therefore allow recognition. We measured the response of fairy-wrens (Malurus cyaneus) to playback of acoustically similar scrubwren (Sericornis frontalis) aerial alarm calls. First, if call similarity prompts escape independent of learning, then fairy-wrens should flee to playback of scrubwren calls outside their geographical range. However, fairy-wrens fled only in sympatry. Second, if call similarity is necessary for learning heterospecific calls, then fairy-wrens should not respond to sympatric species with different calls. We found, on the contrary, that fairy-wrens fled to the very different aerial alarm calls of a honeyeater (Phylidonyris novaehollandiae). Furthermore, response to the honeyeater depended on the specific structure of the call, not acoustic similarity. Overall, call similarity was neither sufficient nor necessary for interspecific recognition, implying learning is essential in the complex task of sifting the acoustic world for cues about danger.
