Year-round vocal activity of two African barbet species

Abstract

ABSTRACT Passive acoustic monitoring is a reliable method to study species behaviour and ecology, enabling the discovery of species activity patterns, especially in remote locations. Here, we conducted a year-long recording study to describe annual and circadian patterns in the vocal activity of two African barbet species, the Yellow-rumped Tinkerbird Pogoniulus bilineatus and the Western Tinkerbird Pogoniulus coryphaea. We used automated software to detect vocalisations of the two species from 4893 one-hour recordings taken in Cameroon. In total, we obtained 31,526 vocalisations of Yellow-rumped Tinkerbirds and 1318 vocalisations of Western Tinkerbirds. We used generalised additive mixed models to determine whether the month or hour of recording or meteorological conditions influenced the species’ vocal activity. Our results indicated that both tinkerbirds are likely seasonal breeders, as the highest vocal activity of both species was during the dry season. Both species exhibited smaller activity peaks in the wet season. Our study provides new information on the vocal activity patterns of two barbet species, which could be valuable in future monitoring and surveying efforts. This study provides an illustrative example of two useful technologies that facilitate studies in remote areas: passive acoustic monitoring for determining species’ activity patterns and automatic recognition software for the rapid analysis of large datasets.