CANTO DE AVES: INTERACÃO ENTRE A POLUIÇÃO SONORA URBANA E SELEÇÃO SEXUAL.

Ambient noise is present almost everywhere in the biosphere. Because background noise can potentially mask the acoustic signals that many animals use to communicate, many species may face a problem when trying to get their messages through noisy environments. Here I reviewed some of the strategies that birds use to deal with ambient noise, and related this information to the possible consequences that may result when birds use their songs in the context of sexual selection, a process that has been widely acknowledged as a main force shaping the evolution of bird songs. I suggest that, depending on the species-specific nature of the sexual selection process in relation to the sender songs, ambient noise may impair the probability of reproduction to different degrees in different species. For instance, species whose songs are effective at communicating in noisy environments, but at the same time render the sender a lowered probability of attracting a mate and defending a territory, may face a greater reduction in reproductive success than if the sender's songs fail in one aspect of sexual selection (e.g. female attraction), but not in the other (e.g. male-male competition). However, more studies are needed if we are to obtain a clearer picture of the possible outcome that may result from the interaction between ambient noise and sexual selection. Some questions that need answers are: to what extent ambient noise impairs the processes of sexual selection in nature? Are sub-oscines equally vulnerable than oscines?El ruido ambiental está presente casi en todos lugares en la biosfera. Debido a que el ruido puede potencialmente enmascarar las señales acústicas que muchos animales usan para comunicarse, varias especies podrían encontrarse con un problema al tratar de transmitir sus mensajes a través de ambientes ruidosos. Aquí hago una revisión de algunas de las estrategias que las aves usan para lidiar con el ruido ambiental y relaciono esta información con las posibles consecuencias que podrían resultar cuando las aves usan sus cantos en el contexto de selección sexual, un proceso que ha sido reconocido ampliamente como una fuerza mayor que moldea la evolución del canto en las aves. Sugiero que, dependiendo de la naturaleza especie-específica de los procesos de selección sexual en relación a los cantos del emisor, el ruido ambiental podría estar menoscabando las probabilidades de reproducción en diferentes grados en distintas especies. Por ejemplo, aquellas especies cuyos cantos son efectivos para comunicar en ambientes ruidosos, pero que al mismo tiempo disminuyen la probabilidad del emisor de atraer una pareja y defender un territorio, podrían enfrentar una reducción mayor en éxito reproductivo que si el canto del emisor falla en un aspecto de selección sexual (p. ej. atracción de la hembra), pero no en otro (p. ej. competencia entre machos). Más estudios son necesarios si queremos obtener una imagen más clara de las posibles consecuencias que podrían resultar de la interacción entre el ruido ambiental y la selección sexual. Algunas de las preguntas que necesitan respuestas son: ¿hasta qué punto el z uido ambiental perjudica los procesos de selección sexual en la naturaleza? ¿Son los sub-oscinos igual de vulnerables que los oscinos?A poluição sonora urbana está presente em quase toda a biosfera. Uma vez que o ruído pode mascarar os sinais acústicos que muitos animais usam para a comunicação, várias espécies poderiam encontrar-se frente ao problema de enviar suas mensagens em um ambiente sonoramente poluído. Aqui faço uma revisão sobre algumas estratégias que as aves usam para enfrentar este problema e relaciono esta informação com as possíveis conseqüências que poderiam resultar quando as aves usam seus cantos no  contexto da seleção sexual, um processo que tem sido amplamente reconhecido como uma força maior que modela a evolução do canto nas aves. Sugiro que, dependendo da natureza espécie - especifica dos processos de seleção sexual em relação aos cantos do emissor, o ruído ambiental poderia estar afetando a possibilidadede reprodução em diferentes graus variáveis de acordo com as espécies. Por exemplo, aquelas espécies em que os cantos são efetivos para comunicar-se em ambientes barulhentos, porém ao mesmo tempo diminuem a probabilidade de o emissor atrair uma parceira e defender um território poderiam enfrentar uma redução maior no êxito reprodutivo que se o canto do emissor falha em relação a um aspecto de seleção sexual (ex., atração da fêmea), porém não em outro (ex., competição entre machos). São necessários outros estudos sequisermos obter uma imagem mais clara das possíveis conseqüências que poderiam resultar da interação entre a poluição sonora do ambiente e a seleção sexual. Algumas das perguntas que precisam ser respondidas são: Até que ponto a poluição sonora ambiental prejudica os processos de seleção sexual na natureza? Os suboscines são tão vulneráveis quanto os oscines

Evidence that traffic noise increases territorial response in vermilion flycatchers

Animals vocalize in particular ways in noise, presumably to increase the probability of detection; however, this idea has been seldom put to the test. Vermilion flycatchers produce longer songs in noisy territories. To test the hypothesis that longer songs increase the probability of detection in noise, we ran a field playback experiment on 30 free-living males. Each male was exposed to two treatments with the same songs, but one treatment had traffic noise and the other had no noise. Half of males were exposed to short songs (with four introductory elements – IE) and half to long songs (eight IE). If long songs have a higher probability of detection in noise, we expected that the experimental noise would have little effect when males heard long songs, but a larger effect when they heard short songs (i.e. significant interaction between song length and treatment). We measured call and flight responses, latencies to call and fly, and closest approach to the speaker. We also measured ambient traffic noise in the males’ territories to evaluate a possible association with their responses. Males did not respond differently to long vs short songs; more importantly, the predicted interaction between song length and treatment was not found. Our results, do not support the hypothesis that long songs are detected with a higher probability in noise. Interestingly, males increased their call response as ambient noise increased in their territories. Males also showed a non-significant trend to increase their flight respond toward long songs with experimental noise than to long songs without noise. Our results strongly suggests that noise amplifies territorial response, which may affect the outcome of territorial competition

Territorial responses to song components in a suboscine, the vermilion flycatcher

Vermilion flycatchers songs are composed of two acoustically different parts: a first part (FP) containing a variable number of introductory elements, and a second part (SP) composed of four elements. Previous work suggests that the FP is important for territorial competition and that it conveys information on threat level. By exposing free-living males to playbacks of complete songs (CS’s), FP’s and SP’s, we evaluated the relative contribution of each song part in males’ territorial responses. Males called in response to all three treatments, suggesting each song component is important for territorial competition. Males’ call response did not differ toward CS’s and FP’s, and toward CS’s and SP’s (although a non-significant tendency was found for SP’s to elicit a weaker response than CS’s), but it was greater toward FP’s than toward SP’s. These results, coupled with previous work, further support the idea that the FP plays a special role during territorial competition and may give information on level of threat. We further discuss our result in terms of mechanistic and functional hypotheses.PostprintPeer reviewe

Increased noise levels have different impacts on the anti-predator behaviour of two sympatric fish species.

types: Journal ArticleCopyright: © 2014 Voellmy et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Animals must avoid predation to survive and reproduce, and there is increasing evidence that man-made (anthropogenic) factors can influence predator-prey relationships. Anthropogenic noise has been shown to have a variety of effects on many species, but work investigating the impact on anti-predator behaviour is rare. In this laboratory study, we examined how additional noise (playback of field recordings of a ship passing through a harbour), compared with control conditions (playback of recordings from the same harbours without ship noise), affected responses to a visual predatory stimulus. We compared the anti-predator behaviour of two sympatric fish species, the three-spined stickleback (Gasterosteus aculeatus) and the European minnow (Phoxinus phoxinus), which share similar feeding and predator ecologies, but differ in their body armour. Effects of additional-noise playbacks differed between species: sticklebacks responded significantly more quickly to the visual predatory stimulus during additional-noise playbacks than during control conditions, while minnows exhibited no significant change in their response latency. Our results suggest that elevated noise levels have the potential to affect anti-predator behaviour of different species in different ways. Future field-based experiments are needed to confirm whether this effect and the interspecific difference exist in relation to real-world noise sources, and to determine survival and population consequences.University of BristolBasler Stiftung für Biologische ForschungDefr

Anthropogenic noise is associated with changes in acoustic but not visual signals in red-winged blackbirds

Some birds in noisy areas produce songs with higher frequency and/or amplitude and altered timing compared to individuals in quiet areas. These changes may function to increase the efficacy of acoustic signals by reducing masking by noise. We collected audio recordings of red-winged blackbirds and measured noise levels. We found that males in noisier places produced songs with fewer syllables and slower repeat rate of elements in some components (rattles). Birds may also improve the efficacy of communication in noise by increasing usage of other signaling modalities. Red-winged blackbirds also perform a visual display in different intensities while singing. We also tested whether this species performs the visual display in different intensities according to current noise levels, and predicted that if the efficacy of songs is impaired in noisy places, males would compensate by performing a more intense visual display. For this, we also collected visual recordings from the same males from which we obtained acoustic recordings. We found no association between acoustic noise and the intensity of the visual display; thus, our results do not support the idea that males are using the visual display as a backup signal to communicate under acoustic noise. We discuss some possible explanations of this negative finding and for the observed noise-related changes in song length and rattle rate in the context of communication under noise

Bird song: the interplay between urban noise and sexual selection

El ruido ambiental está presente casi en todos lugares en la biosfera. Debido a que el ruido puede potencialmente enmascarar las señales acústicas que muchos animales usan para comunicarse, varias especies podrían encontrarse con un problema al tratar de transmitir sus mensajes a través de ambientes ruidosos. Aquí hago una revisión de algunas de las estrategias que las aves usan para lidiar con el ruido ambiental y relaciono esta información con las posibles consecuencias que podrían resultar cuando las aves usan sus cantos en el contexto de selección sexual, un proceso que ha sido reconocido ampliamente como una fuerza mayor que moldea la evolución del canto en las aves. Sugiero que, dependiendo de la naturaleza especie-específica de los procesos de selección sexual en relación a los cantos del emisor, el ruido ambiental podría estar menoscabando las probabilidades de reproducción en diferentes grados en distintas especies. Por ejemplo, aquellas especies cuyos cantos son efectivos para comunicar en ambientes ruidosos, pero que al mismo tiempo disminuyen la probabilidad del emisor de atraer una pareja y defender un territorio, podrían enfrentar una reducción mayor en éxito reproductivo que si el canto del emisor falla en un aspecto de selección sexual (p. ej. atracción de la hembra), pero no en otro (p. ej. competencia entre machos). Más estudios son necesarios si queremos obtener una imagen más clara de las posibles consecuencias que podrían resultar de la interacción entre el ruido ambiental y la selección sexual. Algunas de las preguntas que necesitan respuestas son: ¿hasta qué punto el ruido ambiental perjudica los procesos de selección sexual en la naturaleza? ¿Son los sub-oscinos igual de vulnerables que los oscinos?Ambient noise is present almost everywhere in the biosphere. Because background noise can potentially mask the acoustic signals that many animals use to communicate, many species may face a problem when trying to get their messages through noisy environments. Here I reviewed some of the strategies that birds use to deal with ambient noise, and related this information to the possible consequences that may result when birds use their songs in the context of sexual selection, a process that has been widely acknowledged as a main force shaping the evolution of bird songs. I suggest that, depending on the species-specific nature of the sexual selection process in relation to the sender songs, ambient noise may impair the probability of reproduction to different degrees in different species. For instance, species whose songs are effective at communicating in noisy environments, but at the same time render the sender a lowered probability of attracting a mate and defending a territory, may face a greater reduction in reproductive success than if the sender�s songs fail in one aspect of sexual selection (e.g. female attraction), but not in the other (e.g. male-male competition). However, more studies are needed if we are to obtain a clearer picture of the possible outcome that may result from the interaction between ambient noise and sexual selection. Some questions that need answers are: to what extent ambient noise impairs the processes of sexual selection in nature? Are sub-oscines equally vulnerable than oscines

Anthropogenic noise is associated with changes in acoustic but not visual signals in red-winged blackbirds

Some birds in noisy areas produce songs with higher frequency and/or amplitude and altered timing compared to individuals in quiet areas. These changes may function to increase the efficacy of acoustic signals by reducing masking by noise. We collected audio recordings of red-winged blackbirds and measured noise levels. We found that males in noisier places produced songs with fewer syllables and slower repeat rate of elements in some components (rattles). Birds may also improve the efficacy of communication in noise by increasing usage of other signaling modalities. Red-winged blackbirds also perform a visual display in different intensities while singing. We also tested whether this species performs the visual display in different intensities according to current noise levels, and predicted that if the efficacy of songs is impaired in noisy places, males would compensate by performing a more intense visual display. For this, we also collected visual recordings from the same males from which we obtained acoustic recordings. We found no association between acoustic noise and the intensity of the visual display; thus, our results do not support the idea that males are using the visual display as a backup signal to communicate under acoustic noise. We discuss some possible explanations of this negative finding and for the observed noise-related changes in song length and rattle rate in the context of communication under noise