@article {53424, title = {The buzz segment of Savannah sparrow song is a population marker}, journal = {Journal of Ornithology}, year = {2018}, month = {Mar-12-2018}, abstract = {

Different components of learned birdsongs change at different rates across generations, and the rate of change may correspond to the information carried by each component. To characterize the role of the buzz segment of Savannah sparrow songs, we examined recordings from southeastern Canada and the northeastern US and fully characterized buzz segments in songs recorded from two populations: one on Kent Island, NB, Canada and another in Williamstown, MA, USA. Buzzes varied geographically: Kent Island buzzes had higher mean frequencies and shorter pulse periods than Williamstown buzzes and the differences between the two populations persisted over time. Population-specific buzz characteristics also appeared to be resistant to change. Variants appeared on Kent Island in the late 1980s and were learned by some younger birds; however, these buzz variants disappeared by 2011. We conducted a playback experiment and found that males from both populations had longer responses to local buzzes. Therefore, buzz structure varies geographically; population characteristics of the buzz persist through time despite the introduction of variant forms; and territorial males discriminate between buzzes from different populations. The learned buzz segment of the song may thus serve as a population marker for Savannah sparrows.

}, keywords = {Cultural evolution, dialect, Passerculus sandwichensis, playback, Population, song}, issn = {2193-7192}, doi = {10.1007/s10336-018-1611-7}, url = {http://link.springer.com/10.1007/s10336-018-1611-7}, author = {Williams, Heather and Robins, Clint W. and Newman, Amy E. M. and Freeman-Gallant, Corey R. and Wheelwright, Nathaniel T. and Mennill, Daniel J.} } @article {53396, title = {Sing and do not stray: male rufous-and-white wrens use duets and physical behaviours to guard their mates}, journal = {Animal Behaviour}, volume = {143}, year = {2018}, month = {Jan-09-2018}, pages = {35 - 42}, abstract = {

In diverse animal taxa, breeding partners coordinate their vocalizations to produce vocal duets. One seldom-studied hypothesis for duets is the paternity guarding hypothesis, which states that male animals create duets to advertise their partner\&$\#$39;s mated status and minimize extrapair mating attempts between their partner and other males. We experimentally tested the paternity guarding hypothesis in rufous-and-white wrens, Thryophilus rufalbus, a neotropical duetting songbird. We designed a two-part playback experiment: males first experienced a simulated territorial intrusion by a rival male, and were then given opportunities to answer their female breeding partner\&$\#$39;s songs to create duets. We repeated this experiment during the female\&$\#$39;s fertile and nonfertile breeding stages. In support of predictions of the paternity guarding hypothesis, male wrens created more duets with their partner\&$\#$39;s songs during the fertile period compared to the nonfertile period. Additionally, male wrens appeared to physically guard their mates with greater intensity during the fertile period but did not increase their overall song rates, demonstrating that increased duetting rates during the fertile period were a result of a change in male duetting behaviour, rather than a change in song rate. Our study is among the first to experimentally test the paternity guarding hypothesis for duet function, and suggests that male rufous-and-white wrens use both vocal and physical behaviours to guard their paternity.

}, keywords = {duetting, mate guarding, paternity guarding, rufous-and-white wren, Thryophilus rufalbus, Thryothorus rufalbus}, issn = {00033472}, doi = {10.1016/j.anbehav.2018.07.005}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0003347218302203https://api.elsevier.com/content/article/PII:S0003347218302203?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003347218302203?httpAccept=text/plain}, author = {Kahn, Zachary A. and Moser-Purdy, Christopher and Mennill, Daniel J.} } @article {53364, title = {Quiet violence: Savannah Sparrows respond to playback-simulated rivals using low-amplitude songs as aggressive signals}, journal = {Ethology}, volume = {124}, year = {2018}, month = {Jan-10-2018}, pages = {724 - 732}, abstract = {

When animals compete over resources such as breeding territories, they often use signals to communicate their aggressive intentions. By studying which signals are associated with aggressive interactions, we gain a deeper appreciation of animal behaviour. We studied aggressive signalling in male Savannah Sparrows, Passerculus sandwichensis, focusing on signals that precede physical attack against territorial intruders. We simulated intruders using song playback and taxidermic models, and we determined which behaviours were associated with physical attack. Previous studies that have used this approach suggest that many species produce songs of dramatically lower amplitude, or \“soft songs,\” as signals of aggressive intention. Savannah Sparrows, however, are not known to produce soft songs, and therefore, they provided an interesting system for testing signals that predict attack. Of 93 playback subjects, 23 males attacked the simulated intruder and 70 did not. To our surprise, Savannah Sparrows produced soft songs, and the number of soft songs was a significant predictor of attack on the simulated intruder. Birds also showed a nonsignificant tendency to produce more \“chip\” calls prior to attack on the simulated intruder, whereas three other measured behaviours (aggressive calls, wing waving and passes over the model) did not predict attack. Our study contributes to the growing body of research on aggressive territorial signals and reveals that soft song is an even more widespread signal of aggression in songbirds than previously recognized.

}, keywords = {aggressive signalling, animal communication, low-amplitude vocalizations, Savannah Sparrows, soft songs}, doi = {10.1111/eth.2018.124.issue-1010.1111/eth.12805}, url = {http://doi.wiley.com/10.1111/eth.2018.124.issue-10}, author = {Moran, Ines G. and Doucet, St{\'e}phanie M. and Newman, Amy E. M. and Ryan Norris, D. and Mennill, Daniel J.}, editor = {Koenig, W.} }