Aggression and multi-modal signaling in noise in a common urban songbird

Abstract

Anthropogenic noise may disrupt signals used to mediate aggressive interactions, leading to more physical aggression between opponents. One solution to this problem is to switch signaling effort to a less noisy modality (e.g., the visual modality). In the present study we investigate aggressive behaviors and signaling in urban and rural male European robins (Erithacus rubecula) in response to simulated intrusions with or without experimental noise.First, we predicted that urban birds, living in noisier habitats, would be generally more aggressive than rural birds. We also predicted that during simulated intrusions with experimental noise, robins would increase their physical aggression and show a multi-modal shift, i.e., respond with more visual threat displays and sing fewer songs. Finally, we expected the multi-modal shift in response to noise to be stronger in urban birds compared to rural birds. The results showed that urban birds were more aggressive than rural robins, but an increase in aggression with experimental noise was seen only in the rural birds. Urban but not rural birds decreased their song rate in response to noise. Contrary to the multi-modal shift hypothesis, however, there was no evidence of a concurrent increase in visual signals. These results point to a complex role of immediate plasticity and longer-term processes in affecting communication during aggressive interactions under anthropogenic noise.

Galápagos yellow warblers differ in behavioural plasticity in response to traffic noise depending on proximity to road

“…In the present study, we asked whether Galápagos yellow warblers show increased aggression and flexibility in their song when faced with a simulated intruder in experimentally increased noise. Unlike some of the previous studies showing an increase in aggression levels with increasing ambient noise (Akçay et al, 2020; Davies & Sewall, 2016; Phillips & Derryberry, 2018), or experimental noise (Grabarczyk EE & Gill, 2019; Önsal et al, 2022) we found no effect of experimental traffic noise on physical aggression. Instead, we found that birds on Santa Cruz sang songs with significantly higher minimum frequency than birds on Floreana and, when experimentally exposed to traffic noise, birds in both islands increased the minimum frequency of their songs.…”

“…It is also possible that yellow warblers use signals in other modalities (such as visual modality, e.g. wing-out and tail-spread display) more effectively in increased noise (Akçay & Beecher, 2019; Önsal et al, 2022).…”

“…In support of this scenario, there is evidence from several species of songbirds that high levels of acoustic noise are correlated with increased physical aggression (Akçay et al, 2020; Davies & Sewall, 2016; Phillips & Derryberry, 2018). Of course, increased aggressiveness in urban environments could also be explained by other variables such as resource availability (Foltz et al, 2015), but experimental studies have shown that at least in some cases noise can lead to increased territorial aggression in birds (Grabarczyk & Gill, 2019; Önsal et al, 2022; but see Kleist et al, 2016).…”

A Quieter Ocean: Experimentally Derived Differences in Attentive Responses of Tursiops truncatus to Anthropogenic Noise Playbacks before and during the COVID-19-Related Anthropause

“…Anemone fish ( Amphiprion chrysopterus [ 80 ]) exposed to intermittent motorboat noise stayed closer to their anemone and responded with increased territorial aggression toward heterospecifics [ 81 ]. When anthropogenic noise increased in rural territories, the European Robin ( Erithacus rubecula [ 14 ]) displayed an increase in aggression [ 82 ]. Urban robins responded with more behaviors that are aggressive to simulated intrusions.…”

Artificial Green Corridors in an Andean City as Effective Support of Avian Diversity

“…For instance, it could mask parent-offspring communication, hamper the transmission of mate quality information through bird songs, reduce the quality of the territory, induce physiological stress in chicks, impair their development [54], and alter the perceptions of predators [55] or prey [56]. Noise can also induce shifts in the frequency of vocal signals to visual or physical ones [57], direct modifications of song characteristics, higher frequencies of bird singing in noisy environments [58], and even the cultural evolution of songs [59,60]. However, tolerance to noise and other human disturbances varies across species and should also reflect adaptations to urban environments, as the consequence of species turnover is not random [56].…”