The aim of our study was to address the functional role of nocturnal song in the Field Sparrow (Spizella pusilla), particularly in the context of acquiring extra-pair mates. Field Sparrow is a diurnal species that occasionally conduct extraterritorial forays and sing at night. While males and females conduct forays to seek extra-pair mates, females usually enter the territories of the extra-pair males that ultimately sired their offspring. The mechanism used by females to locate potential extra-pair sires, however, is still unknown. We used autonomous acoustic recording units (ARUs) and an automated detection and classification system to examine the associations of nocturnal singing behavior of mated field sparrows with social factors (fertility stage, presence of neighbor song and presence of intruder song). Additionally, we used an automated radio telemetry system (ARTS), ARUs, and automated playback systems to conduct a nocturnal playback experiment and explore how mated male and female field sparrows responded to nocturnal single songs at night and across prefertile, fertile, and postfertile stages. Our study showed that nocturnal song in the field sparrow may play a role in extra-pair mate attraction (intersexual function), specifically the announcement of the presence or availability of extra-pair males to females, either through territorial males vocalizing to foraying or neighboring females or through intruder males vocalizing to females on her territory. Our study, particularly when combined with other data on foray behavior, provides a clearer, more comprehensive understanding of the role of nocturnal song as an extra-pair mating behavior.
|Title of host publication
|6th North American Ornithological Conference, 16-21 August, 2016, Washington, D.C.
|Published - 2016