Different Messages are Transmitted by Individual Duet Contributions and Complete Duets in a Species with Highly Overlapped Duets

Abstract

Background: Duet function hypotheses have been mostly studied in bird species that produce duets with male and female solo songs. However, in order to understand if patterns of duet function are similar across all duetting species, it is highly necessary to test the duet function hypotheses in species that produce duets with vocalizations other than solo songs. Objective: We studied the responses of territorial pairs to each sex’s individual duet contribution and complete duets in a species that produces duets with a vocalization other than male and female solo songs. Methods: We conducted a playback experiment where we presented duet contributions of each sex to three populations of White-eared Ground-sparrows (Melozone leucotis) in Costa Rica, during this species’ breeding season in 2016. Results: The responses to complete duets were stronger than those to each sex’s duet contribution, suggesting that complete duets and each sex’s duet contribution have different functions. Complete duets are used to protect resources from intruders (supporting the resource defense hypothesis), and to prevent the partner from being usurped by intruders (supporting the mate-guarding hypothesis). Males used solo songs in response to female duet contributions, and this may work to attract intruder females (increasing the probability of extra-pair copulation). Males also use solo songs in response to male duet contributions, which may work as a signal to repel intruder males and guard their female. In this case, where mate attraction occurs with a completely different type of vocalization than used for duetting, we found a clear pattern of a double agenda for males when a territorial intrusion occurs. Conclusions: This study provides strong support for the dual function hypothesis in duets and reveals conflicting selective pressures between pair members relative to each hypothesis.

Yellow‐breasted Boubous (Laniarius atroflavus) jointly defend territories with male‐led duets against stranger pairs, males and females

“…White-eared Ground Sparrows (Melozone leucotis) show multi-functionality in duets. The response to playbacks of duets for this species showed an aggressive response to duets by the pair, indicating resource defence; however, depending on the sex, members of pairs would react more to same-sex signallers, indicating conflict functions (Sandoval et al, 2018). Yellow-breasted…”

“…White‐eared Ground Sparrows ( Melozone leucotis ) show multi‐functionality in duets. The response to playbacks of duets for this species showed an aggressive response to duets by the pair, indicating resource defence; however, depending on the sex, members of pairs would react more to same‐sex signallers, indicating conflict functions (Sandoval et al., 2018). Yellow‐breasted Boubous respond strongly towards duet and male solo playback, compared with female solo vocalisations, which can be interpreted as a way of male mate‐guarding behaviour.…”

Behavioral, morphological, and ecological trait evolution in two clades of New World Sparrows (AimophilaandPeucaea, Passerellidae)

“…Avian duets have been shown to perform a range of functions, including joint resource defense, mate defense, and pair coordination (Hall, 2009;Dahlin & Benedict, 2014). Work on the genera Melozone and Peucaea has demonstrated that duets of different species have similar functions in resource defense, providing a possible selective pressure maintaining this trait (Benedict, 2010;Sandoval, Méndez & Mennill, 2013;Illes, 2015;Sandoval, Juárez & Villarreal, 2018). Similarly, studies of other New World avian clades have shown that vocal duet presence and form are often evolutionarily conserved (Mann et al, 2009;Mitchell et al, 2019).…”

La voz de nuestras aves: contribuciones de la bioacústica a la ornitología colombiana

“…Además, los patrones de actividad vocal pueden diferir entre especies, por ejemplo, mientras el tinamú ondulado (Crypturellus undulatus) es vocalmente más activo en el día; algunas aves como los bienparados (e.g., Nyctibius griseus y N. grandis) prefieren vocalizar más por las noches o madrugadas (Pérez-Granados & Schuchmann 2020). Otros escenarios nos acercan al entendimiento de conductas complejas de cooperación donde ambos sexos participan e interactúan para consolidar repertorios en duetos cumpliendo funciones en la defensa de territorios, recursos y pareja (Sandoval et al 2018). Ciertamente, la bioacústica nos permitirá seguir entendiendo los patrones de actividad vocal en aves, lo que a su vez nos proporcionará información necesaria para realizar estudios comparativos entre poblaciones y especies y que finalmente nos permitirá tener un mejor panorama sobre los orígenes de la diversidad vocal.…”