Roaring dynamics in rutting male red deer Cervus elaphus from five Russian populations

Abstract

In Russia, current populations of Cervus elaphus sensu lato represent a mix of fragmented remnants of ancestral red deer naturally radiated from their center of origin in Middle Asia and populations, either re-stored by people at places where the native red deer are extinct or kept for agricultural production. Male rutting roaring activity represents an important part of red deer reproduction but there are no methods for unified evaluation of roaring dynamics. This study proposes the criteria for subdividing the entire rut period to phases (start, active, fading), applicable irrespectively to differences in population geographical area, animal density, subspecies or absolute values of call number per hour. With this approach, we estimate stag rutting roaring activity on hourly basis in five populations of red deer belonging to three subspecies by using two spaced automated recording devices per population, recording roars for 5 min/hour, 24 h/day, for 52-60 days of rutting period. Two spaced recorders per population provided similar data on rut dynamics, although absolute values of call number per hour were different. In four of the five study populations, rut period covered approximately the same calendar dates, from the last days of August until the last ten days of October. The mean roaring activity over a rut period differed strongly between populations (from 4-15 calls/h to 319-377 calls/h). Effects of time of day on roaring activity differed between rut phases. The possible reasons of this variability are discussed.