Biology subjects

Beecher, M. D.

Publications and source records attributed to Beecher, M. D..

5 recordsLinked to original sources

bioRxiv2020

Song sparrows do not discriminate between their own song and stranger song

Bird song is socially learned. During song learning, the birds hearing its own vocalization is important for normal development of song. Whether birds own song is represented and recognized as a special category in adult birds, however, is unclear. If birds respond differently to their own songs when these are played back to them, this would be evidence for auditory self-recognition. To test this possibility, we presented song sparrow males (Melospiza melodia) playbacks of their own songs or stranger songs and measured aggressive responses as well as type matching. We find no evidence of behavioral discrimination of birds own song relative to the (non-matching) stranger song. These findings cast doubt on an earlier proposal that song sparrows display auditory self-recognition and support the common assumption in playback experiments that birds own song is perceived as stranger song.

animal behavior and cognition↗

bioRxiv2019

Territory establishment, song learning strategies and survival in song sparrows

In most songbirds the processes of song learning and territory establishment overlap in the early life of young birds who usually winds up with songs matching those of their territorial neighbors in their first breeding season. In the present study, we examined the relationships among the timing of territory establishment, the pattern of song learning and territorial success in a sedentary population of song sparrows (Melospiza melodia). Males in this population show high song sharing within neighborhoods derving from their learning most of their songs from neighboring males. These shared songs are preferentially used in interactions with neighbors. Males also show significant variation in the timing of territory establishment, ranging from their first summer until the next spring. Using a three-year dataset, we found that the timing of territory establishment did not systematically affect the composition of the song repertoire of the tutee: early establishers and late establishers learned equally as much from their primary tutors, and had a similar number of tutors and repertoire size. Timing of territory establishment also did not have an effect on subsequent survival on territory. Therefore, the song learning program of song sparrows seems versatile enough to lead to high song sharing even for birds that establish territories relatively late.

animal behavior and cognition↗

bioRxiv2019

Bird Song Learning is Mutually Beneficial for Tutee and Tutor

Song learning is generally assumed to be beneficial for a young songbird, but merely incidental, without costs or benefits, for the older song tutors. In the present study we contrast two mutually exclusive hypotheses about the tutor/tutee relationship: (1) that it is cooperative, or at least mutually tolerant, with tutor and tutee mutually benefiting from their relationship, vs. (2) that it is competitive, with tutor and tutee competing over territory, so that one or the other suffers negative fitness consequences of their relationship. In a field study of three consecutive cohorts of song sparrows (Melospiza melodia) we determined the older bird (primary tutor) from whom the young bird (tutee) learned most of his songs, and how long tutee and primary tutor survived subsequently. We found that the more songs a tutee learns from his primary tutor, the longer their mutual survival on their respective territories. This study provides the first evidence of a mutual benefit of bird song learning and teaching in nature.

animal behavior and cognition↗

bioRxiv2019

Multi-modal communication: Song sparrows increase signal redundancy in noise

Although the effects of anthropogenic noise on animal communication have been studied widely, most research on the effect of noise in communication has been on communication in a single modality. Consequently, how multimodal communication is affected by anthropogenic noise is relatively poorly understood. Here we ask whether song sparrows (Melospiza melodia) show evidence of plasticity in response to noise in two aggressive signals in acoustic and visual modalities. We test two hypotheses: (1) that song sparrows will shift signaling effort to the visual modality (the multi-modal shift hypothesis), and (2) that they will increase redundancy of their multi-modal signaling (the back-up hypothesis). We presented male song sparrows with song playback and a taxidermic mount with or without a low-frequency acoustic noise from a nearby speaker. We found that males did not switch their signaling effort to visual modality (i.e., wing waves) in response to the noise. However, the correlation between warbled soft songs and wing waves increased in the noise treatment, i.e. signals became more redundant. These results suggest that when faced with anthropogenic noise, song sparrows can increase redundancy of their multi-modal signals, which may aid in robustness of the communication system.

animal behavior and cognition↗

bioRxiv2017

Good tutors are not Dear Enemies in Song Sparrows

Bird song 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 respond more aggressively to songs of their tutors than they do 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.

animal behavior and cognition↗