Communication breakdown! How information loss affects behavioral responses in the Great-Billed Seed-Finch, Sporophila maximiliani (Thraupidae: Passeriformes)

Abstract Communication is a central process in animals' interactions and the transmission of information depends on the signal quality. As signals degrade, the resulting loss of information has the potential to increase the ambiguity about the interaction context. Thus, the information loss has the potential to generate stress and motivational conflict, as has already been demonstrated for anuran species. We tested whether the information loss affects the behavioral response of Sporophila maximiliani using (i) a playback experiment, to simulate an acoustic signal, and (ii) a mirror experiment, to simulate a visual signal. We found that the quality of the acoustic signal and, therefore, the quality of information, affected the behavior of the species. The degradation of the acoustic signal increased the emission of maintenance behaviors, which suggests an increase in stress and a state of motivational conflict. Also, calls’s modulation from lower to higher peak frequency indicates that fear is driving such behavioral changes. Conversely, the degradation of visual signal resulted in lower stress, with a decrease in alert and maintenance behaviors displays. We found that the signal degradation and the loss of information can change the motivational state of S. maximiliani when exposed to degraded acoustic signals and result in a motivational conflict due to the ambiguity of the interaction context. The emission of maintenance behaviors as displacement activities is an indicator of the higher stress endured by the individuals exposed to partially degraded signals. Furthermore, a partially comprehensible signal is more harmful than a totally degraded one.