@article {57582, title = {Habitat-related differences in song structure and complexity in a songbird with a large repertoire}, journal = {BMC Ecology}, volume = {19}, year = {2019}, month = {Jan-12-2019}, abstract = {

Background

Urbanisation has been shown to influence many aspects of animal vocal communication. Much attention has been paid to anthropogenic noise, which is often described as one of the most challenging disturbances for urban dwellers. While a large body of literature describes associations between vocal behavior of avian populations and background noise level, most of these studies were conducted on species with relatively simple songs and small repertoire sizes. This study focuses on the song thrush, Turdus philomelos, a common Eurasian songbird with a complex singing style and large syllable repertoire. Our objective was to determine whether frequency, repertoire and temporal organisation of song parameters vary between birds inhabiting urban and adjacent forest habitats in which ambient noise levels differ.

Results

Songs of urban males were found to be more complex than in conspecifics from natural forest populations. Urban dwellers possessed greater syllable repertoires and repeated syllable sequences more often. In addition, they used a smaller proportion of whistles and a higher proportion of twitter syllables when singing compared to the nonurban males. Moreover, we found significant differences in the minimum and peak frequency of the whistle syllable between studied populations.

Conclusions

These findings may be an example of adaptation of acoustic communication in noisy urban environments, but we also discuss other possible explanations. We emphasize the need for further investigation into the relationships between birdsong and habitat characteristics, male quality, population density and ambient noise level in populations occupying urban and nonurban habitats.

}, keywords = {animal communication, anthropogenic noise, birdsong, songbirds, Turdus philomelos, Urban ecology, urbanisation}, doi = {10.1186/s12898-019-0255-7}, url = {https://bmcecol.biomedcentral.com/articles/10.1186/s12898-019-0255-7}, author = {Deoniziak, Krzysztof and Osiejuk, Tomasz S.} } @article {57346, title = {Evidence for differing trajectories of songs in urban and rural populations}, journal = {Behavioral Ecology}, year = {2019}, month = {Jul-08-2020}, abstract = {

Learned traits, such as foraging strategies and communication signals, can change over time via cultural evolution. Using historical recordings, we investigate the cultural evolution of birdsong over nearly a 50-year period. Specifically, we examine the parts of white-crowned sparrow (Zonotrichia leucophrys nuttalli) songs used for mate attraction and territorial defense. We compared historical (early 1970s) recordings with contemporary (mid-2010s) recordings from populations within and near San Francisco, CA and assessed the vocal performance of these songs. Because birds exposed to anthropogenic noise tend to sing at higher minimum frequencies with narrower frequency bandwidths, potentially reducing one measure of song performance, we hypothesized that other song features, such as syllable complexity, might be exaggerated, as an alternative means to display performance capabilities. We found that vocal performance increased between historical and contemporary songs, with a larger effect size for urban songs, and that syllable complexity, measured as the number of frequency modulations per syllable, was historically low for urban males but increased significantly in urban songs. We interpret these results as evidence for males increasing song complexity and trilled performance over time in urban habitats, despite performance constraints from urban noise, and suggest a new line of inquiry into how environments alter vocal performance over time.

}, keywords = {anthropogenic noise, birdsong, Cultural evolution, sexual selection, Urbanization, vocal performance}, issn = {1045-2249}, doi = {10.1093/beheco/arz142}, url = {https://academic.oup.com/beheco/advance-article/doi/10.1093/beheco/arz142/5551107}, author = {Moseley, Dana L and Jennifer N. Phillips and Derryberry, Elizabeth P and David A. Luther}, editor = {Candolin, Ulrika} } @article {53411, title = {Context-dependent variation of house finch song syntax}, journal = {Animal Behaviour}, volume = {147}, year = {2019}, month = {Jan-01-2019}, pages = {33 - 42}, abstract = {

We explored the role of social context in the syntactical variation of house finch, Haemorhous mexicanus, songs using both traditional song measures and network analysis. In comparison to solo bouts, the bouts of countersinging males had increased syntax diversity, with higher numbers of simple paths and transition types (but not syllable types) in comparison to solo song, which had high sequence consistency. Both the proportion of introductory syllables and the degree (number of transitions to and from those syllables) increased in countersinging bouts and were an important source of syntactic variability. In contrast, courtship bouts included longer songs and longer syllables than both solo and countersinging bouts, but were similar to solo songs in sequence consistency. The longest courtship songs often included concatenated sequences that formed \‘compound songs\’, or repeating strings of main song syllables, which slightly increased the degree of those syllables. Our results suggest that interactions between males are associated with increased syntactic variability in song delivery while female choice favours signals that maintain species-typical syntax and demonstrate fitness in terms of a male\&$\#$39;s capacity to sing extended songs.

}, keywords = {birdsong, countersinging, courtship, network analysis, sequence consistency, social context, syntax}, issn = {00033472}, doi = {10.1016/j.anbehav.2018.11.001}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0003347218303373https://api.elsevier.com/content/article/PII:S0003347218303373?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003347218303373?httpAccept=text/plain}, author = {Ciaburri, Ivy and Williams, Heather} }