Dialects of an invasive songbird are preserved in its invaded but not native source range

Abstract

Biological invasions are not only events with substantial environmental and socioeconomic impacts but are also interesting natural experiments, allowing the study of phenomena such as the cultural evolution of bird song following introduction. We took an excellent opportunity to compare the distribution of dialects of the yellowhammer Emberiza citrinella, a small Eurasian passerine, in its native source region (Great Britain) and invaded range (New Zealand) more than hundred years after relocation. Recent field recordings (including those provided by volunteers within a citizen science project) were complemented by those from archives, each assigned to appropriate dialect by visual inspection of a sonogram, and the resulting spatial patterns of dialect distribution were interpreted using historical data on the yellowhammer invasion. The two countries differ markedly in the composition and distribution of dialects. New Zealand populations sing a greater number of different dialects, seven in total, five of which were not detected in the current British population, but have been reported by previous studies from the continental Europe. Two identified localities of capture (Brighton, Sussex, UK) and release (Dunedin, Otago, NZ) differ even more strikingly, having no dialects in common. The largely sedentary nature of yellowhammers allows for two mutually exclusive explanations for European dialects being detected in New Zealand but not in Great Britain: 1) the corresponding song types have emerged de novo in New Zealand, through convergent cultural evolution; 2) the dialects have disappeared from Great Britain, while being preserved in New Zealand. Indirect evidence from the widespread occurrence of these dialects in continental Europe and the reported stability of yellowhammer song, supports the latter explanation. We suggest that the yellowhammer dialect system is an avian equivalent of a phenomenon already noted in human languages, in which ancient words or structures are retained in expatriate communities. IntroductionBiological invasions can be a potential threat to the environment (Pyšek et al. 2012, Kumschick et al. 2015, Martin-Albarracin et al. 2015 and economy (Pimentel et al. 2005, Kettunen et al. 2009), but they can also provide a golden opportunity to study evolutionary, behavioural or ecological phenomena on spatial and temporal scales ResearchDialects of an invasive songbird are preserved in its invaded but not native source range

Cultural Transmission, Evolution, and Revolution in Vocal Displays: Insights From Bird and Whale Song

“…The information on the rate of change of songs in newly established populations is mixed. Songbirds introduced to (and colonizing) areas well outside their natural geographical range may show a slower rate of song change (e.g., chaffinches Fringilla coelebs introduced to New Zealand from Sussex, UK; Ince et al, 1980 ; Jenkins and Baker, 1984 ) and may retain dialect variation that has been lost from the source population (e.g., yellowhammers Emberiza citronella ; Pipek et al, 2018 ). But can also show rapid cultural evolution (e.g., Eurasian tree sparrows Passer montanus introduced to the USA; Lang and Barlow, 1997 ).…”

“…The rapid (within season) and extensive (ocean basin-wide) spreading waves of song replacement represents an extreme example of song change that has the potential to increase our understanding of cultural transmission in general. While cultural evolution of song in birds has been widely documented (e.g., Williams et al, 2013 ; Pipek et al, 2018 ), sometimes at a continent-wide scale (e.g., Otter et al, 2020 ), we are aware of only one songbird species, the corn bunting [ Emberiza (Miliaria) calandra ], that shows concerted change in details of local dialects from year to year ( McGregor et al, 1997 ). Therefore, the aim of this paper is to compare humpback whale song revolutions with the cultural evolution of song in birds (focusing on corn buntings) and to identify the sort of data that would be required to test some of the possible explanations, both in birds and whales.…”

“…Examples include the pioneering study on song sparrows Melospiza melodia ( Nice, 1943 ; since extended by Beecher’s lab, e.g., Beecher, 2017 ; Beecher et al, 2020 ), Bewick’s wren Thryothorus bewickii ( Kroodsma, 1974 ), saddlebacks Philesturnus carunculatus ( Jenkins, 1978 ) and Philesturnus rufusater ( Parker et al, 2012 ), indigo buntings Passerina cyanea ( Payne, 1981 ; Payne and Payne, 1993 ), great tits Parus major ( McGregor and Krebs, 1982 ), and savannah sparrows Passerculus sandwichiensis ( Wheelwright et al, 2008 ). An approach using unidentified singers recorded continent‐ or country-wide by many workers including citizen scientists (e.g., Pipek et al, 2018 ; Otter et al, 2020 ) can allow cultural evolution to be documented on comparable spatial scales to whale song. While lacking the control of lab studies, field studies do take place in a natural social context.…”

Song: The Learned Language of Three Major Bird Clades

“…Just recently, an exciting newsflash announced that lost birdsong had been discovered in introduced Yellowhammer populations from New Zealand. There, far beyond the species' native breeding range on the other side of the globe, some dialect types were registered that apparently went lost in the British area of origin of the species (Pipek et al 2017). In analogy to population genetic processes, such timely change of local song repertoires has been considered a merely stochastic effect termed cultural drift (Lynch 1996).…”

Detailed large‐scale mapping of geographical variation of Yellowhammer Emberiza citrinella song dialects in a citizen science project

“…, Pipek et al . ). The present‐day availability of digital recording devices and online communication with participants makes involvement of the public much easier than in the past (Newman et al .…”