White-throated sparrows alter songs differentially in response to chorusing anurans and other background noise

Abstract. Background noise can interfere with acoustic communication. Signal modifications have the potential to increase signal-to-noise ratios and reduce the masking effect of noise. Immediate signaling flexibility, a type of vocal plasticity, allows animals to modify their signal to optimize transmission depending on ambient noise conditions. Results from previous studies provide conflicting evidence about whether expression of immediate signaling flexibility is dependent upon the signaler having prior experience with noisy environments. To improve our understanding of vocal plasticity, we examined immediate signaling flexibility in white-crowned sparrows Zonotrichia leucophrys nuttalli in urban and rural locations. We experimentally broadcast noise with three different spectral profiles-city (low frequency), inverse of city (high frequency), and white (equal intensity at all frequencies)-successfully to 107 males and measured multiple features of songs produced prior to and during the experiment. We predicted that all males would adjust their song structure during the noise broadcast, but that the extent of plasticity would be greater in noisier territories and the manner of adjustment would depend on the type of experimental noise broadcast. Instead, we found that only urban males exhibit immediate signaling flexibility, through which bandwidth decreases in response to experimental noise. Signal modification did not change with type of noise broadcast or territory background noise. Although songs were less flexible than predicted, the relative reduction in signal bandwidth in urban birds could improve their signal-to-noise ratio during the noise broadcast.

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“…, Goodwin and Podos , Montague et al. , Potvin and Mulder , Lenske and La , LaZerte et al. , frog, Hanna et al.…”

Section: Introductionmentioning

confidence: 99%

Immediate signaling flexibility in response to experimental noise in urban, but not rural, white‐crowned sparrows

et al. 2017

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“…), can shape song frequency adjustments in birds (Lengagne et al . , Brumm & Zollinger , Lenske & La , Hart et al . ).…”

Section: Discussionmentioning

confidence: 97%

Multiple signaling in a variable environment: expression of song and color traits as a function of ambient sound and light

Simpson

McGraw

2018

Biotropica

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Many animals communicate using more than one signal, and several hypotheses exist to explain the evolution of multiple signals. However, these hypotheses typically assume static selection pressures, and previous work has not addressed how spatial and temporal environmental variation can shape variation in signaling systems. In particular, environmental variability, such as ambient lighting or noise, may affect efficacy (e.g., detectability/perception by receivers) of signals. To examine how signal expression varies intraspecifically as a function of habitat characteristics, we evaluated relationships between spatial environmental variation and song and plumage color expression in a tropical songbird, the Red‐throated Ant‐tanager (Habia fuscicauda) in Panama. We recorded male ant‐tanager song, plucked feathers to measure coloration, and quantified the acoustic and light environments from each male's territory. In addition, we took several morphological measurements from each male to assess the potential information content of song and plumage color. We found that males with redder and more saturated crown plumage occurred on darker territories, and males that sang shorter and lower frequency songs occurred on noisier territories. We also found that more colorful males tended to sing longer and lower frequency songs. Finally, we found that song and color correlated similarly with male morphology (e.g., tarsus length, body mass). Altogether, these results indicate that spatial variation in the environment is related to male coloration and song, and that males might be optimizing color and song expression for their particular territorial environment.

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“…; Arroyo‐Solís et al. ; Lenske & La ). This fact indicates that while background noise is a factor that masks acoustic signals, birds can adapt to such conditions.…”

Section: Discussionmentioning

confidence: 99%

“…) or song length (Ríos‐Chelén et al. ; Lenske & La ), when singing in noisy conditions. However, our data do not support the predictions that chaffinches behave in a similar way when faced with anthropogenic noise.…”

Section: Discussionmentioning

confidence: 99%

Disentangling Relations among Repertoire Size, Song Rate, Signal Redundancy and Ambient Noise Level in European Songbird

Deoniziak

Osiejuk

2016

Ethology

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The majority of male songbirds have small repertoires and sing with eventual variety; that is, they present one song type several times before switching to the next one. Several hypotheses have been proposed to explain this phenomenon. The antiexhaustion hypothesis argues that song‐type switching prevents muscle fatigue in the syrinx. The signal redundancy hypothesis suggests that repeating the same signal increases transmission success. Here, we have studied the song behaviour of the chaffinch, Fringilla coelebs, a common Eurasian species in which the males sing a few different song types and provide eventual variety. We tested different hypotheses to explain the temporal organisation of song output (repertoire size, song rate, bout duration, etc.) as a function of ambient noise by comparing birds from the same macrogeographic region in which the birds live either in a noisy town (n = 71) or in a quieter forest habitat (n = 68). Contrary to the prediction of the signal redundancy hypothesis and the results of earlier work on chaffinches living close to noisy streams, we found no significant differences in song characteristics between the town and forest populations. Our results support the antiexhaustion hypothesis because males with larger repertoires were able to sing with a significantly higher rate due to faster switching between different song types and producing shorter bouts. Sample size or population differences between our study and earlier investigations of the same species may explain the inconsistency with previous findings. Future studies should focus on determining the relations between song organisation and the directly measured quality of males and females' choice using, preferably, a longitudinal approach.

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White-throated sparrows alter songs differentially in response to chorusing anurans and other background noise

Cited by 18 publications

References 41 publications

Immediate signaling flexibility in response to experimental noise in urban, but not rural, white‐crowned sparrows

Immediate signaling flexibility in response to experimental noise in urban, but not rural, white‐crowned sparrows

Multiple signaling in a variable environment: expression of song and color traits as a function of ambient sound and light

Disentangling Relations among Repertoire Size, Song Rate, Signal Redundancy and Ambient Noise Level in European Songbird

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