Purpose of Crested Francolin Ortygornis sephaena male collective calls at dusk based on livestream audio censusing

Abstract

The study of diel and seasonal variation in vocal interactions of Crested Francolin Ortygornis sephaena territorial males helps clarify its purpose, thus delivering insights into the behavioural ecology of this species. The goals of the present paper are to describe the vocal footprint of neighbouring Crested Francolin territorial males and understand the purpose of collective calls. We logged remotely into a HD webcam with microphone located in Tembe Elephant National Park (KwaZulu-Natal, South Africa) to listen to male vocal exchanges from August 2018 to November 2019. Territorial call exchanges among three neighbouring males at dusk took place at the onset of, but not during, the breeding season and then again during the non-breeding season. In the latter case vocalisations were emitted even beyond dusk time. Call duration and intensity (calls per minute) did not increase at the onset of the breeding season. Males exchanged calls in a leader-follower manner seemingly unrelated to female attraction and guarding. On the contrary, this cordial collective calling is likely a form of cooperation to detect vocal responses by interlopers.