@article {50506, title = {Responses of male cricket frogs ( Acris crepitans) to attenuated and degraded advertisement calls}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-05-2017}, pages = {357 - 364}, abstract = {

We examined the vocal and non-vocal responses of male cricket frogs (Acris crepitans) to conspecific advertisement calls that had been attenuated or degraded by reducing the depth of amplitude modulation (AM). Both are characteristic of changes to the call as it is transmitted through natural habitats. As stimulus calls became more intense or less degraded, male cricket frogs gradually decreased their call rate and increased the number of call groups and pulse groups in their calls, changes indicative of increased aggressive interactions. At the higher intensities and lower degradation levels, the probability that males would shift to one of two non-vocal behavioral responses, attacking the perceived intruder or ceasing calling and abandoning the call site, gradually increased. The results show that differences in signal attenuation and AM degradation levels are perceived by males and trigger both vocal and non-vocal behavioral responses consistent with their use in evaluating the distance to a challenging male. Furthermore, the results indicate that the male responses are graded, increasing as intensity rises and degradation falls, and hierarchical, with vocal responses preceding behavioral responses over the range of intensities and degradation levels presented.

}, keywords = {acoustic communication, aggression, amphibians, cricket frogs}, doi = {10.1111/eth.2017.123.issue-510.1111/eth.12602}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-5}, author = {Venator, Kurt R. and Michael J. Ryan and Wilczynski, Walter}, editor = {Koenig, W.} } @article {50504, title = {Good tutors are not dear enemies in song sparrows}, journal = {Animal Behaviour}, volume = {129}, year = {2017}, month = {Jan-07-2017}, pages = {223 - 228}, abstract = {

Birdsong is the most widely studied example of vocal learning outside human language and shares important parallels with it, including the importance of social factors during development. Our understanding of how social factors affect song learning, however, remains surprisingly incomplete. Here we examine the possible role of aggressive interactions in determining song \‘tutor\’ choice in song sparrows, Melospiza melodia, a songbird in which individuals display song learning strategies ranging from learning primarily from one tutor, to learning a few songs each from a number of tutors. We test two hypotheses: the competition hypothesis suggests that young birds learn more from tutors with whom they compete especially intensely and predicts that tutees will respond with high aggression to tutor songs. In contrast, the cooperation hypothesis suggests that song learning reflects a cooperative relationship between the tutor and the tutee and predicts that tutees will respond with low aggression to tutor songs. In a playback experiment we found that birds responded more aggressively to songs of their tutors than they did to songs of strangers and that the strength of aggressive response correlated positively with how much they had learned from that tutor. These results provide the first field evidence for the hypothesis that young males preferentially learn their songs from adult males with whom they compete most intensely during the song-learning phase, and perhaps afterwards.

}, keywords = {aggression, communication, cooperation, social learning, song learning}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.05.026}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217301719}, author = {Ak{\c c}ay, {\c C}a{\u g}lar and Campbell, S. Elizabeth and Beecher, Michael D.} }