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

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

Editorial: effects of artificial light at night on organisms: from mechanisms to function

No abstract available

Intra-specific brood parasitism revealed by DNA micro-satellite analyses in a sub-oscine bird, the vermilion flycatcher Parasitismo intraespecífico revelado mediante análisis de microsatélites de ADN en un ave suboscina, el cardenalito o saca tu real

Extra-pair reproduction is known to occur in many avian species. However, among passerines, the majority of studies on extra-pair reproduction have been carried out in oscine birds from temperate regions. Conversely, sub-oscines species, and particularly, species that inhabit tropical regions, have been studied to a much lesser extent. Given that a majority of avian species live in the tropics, it is important to study more tropical and sub-oscine species to have a more accurate picture of the rates of extra-pair reproduction among passerines, and a better understanding of the adaptive function of extra-pair reproduction in birds. Tropical species differ from temperate species in several ecological and life history traits, that may influence the occurrence of different modes of extra-pair reproduction and their prevalence. In this study we asked whether extra-pair reproduction occur in a sexually dimorphic and socially monogamous sub-oscine, the vermilion flycatcher (Pyrocephalus rubinus). We report cases of extra-pair paternity, extra-pair maternity and intra-specific brood parasitism, and discuss our results in the view of other studies with passerinesSe sabe que la reproducción extrapareja ocurre en muchas especies de aves. Sin embargo, entre paserinos, la mayoría de los estudios se han llevado a cabo en aves oscinas de regiones templadas. Por el contrario, las especies suboscinas, y en particular las especies que habitan regiones tropicales, se han estudiado mucho menos. Por lo tanto, es importante estudiar más especies tropicales y suboscinas para tener una visión más acertada de las tasas de reproducción extrapareja en paserinos y un mejor entendimiento de la función adaptativa de la reproducción extrapareja en aves. Las especies tropicales difieren de las especies que habitan regiones templadas en diversos rasgos ecológicos y de historia de vida, que podrían influir en las tasas de ocurrencia de diferentes modos de reproducción extrapareja. En este estudio nos preguntamos si ocurre o no la reproducción extrapareja en el cardenalito o saca tu real (Pyrocephalus rubinus), un suboscino sexualmente dimórfico y socialmente monógamo. Reportamos casos de paternidad extrapareja, maternidad extrapareja y parasitismo intraespecífico, y discutimos nuestros resultados bajo la luz de otros estudios en paserino

Female happy wrens select songs to cooperate with their mates rather than confront intruders

Vocal duetting occurs in many taxa, but its function remains much-debated. Like species in which only one sex sings, duetting birds can use their song repertoires to signal aggression by singing song types that match those of territorial intruders. However, when pairs do not share specific combinations of songs (duet codes), individuals must choose to signal aggression by matching the same-sex rival, or commitment by replying appropriately to their mate. Here, we examined the song types used by female happy wrens (Pheugopedius felix) forced to make this decision in a playback experiment. We temporarily removed the male from the territory and then played songs from two loudspeakers to simulate an intruding female and the removed mate's response, using song types that the pair possessed but did not naturally combine into duets. Females were aggressive towards the female playback speaker, approaching it and overlapping the female playback songs, but nevertheless replied appropriately to their mate's songs instead of type matching the intruding female. This study indicates that females use song overlapping to signal aggression but use their vocal repertoires to create pair-specific duet codes with their mates, suggesting that duetting functions primarily to demonstrate pair commitment