Passive acoustic monitoring of roaring activity in male Wapiti Cervus elaphus xanthopygus in Far East of Russia: effects of recording site, temperature and time of day

Passive acoustic monitoring is an actual tool for population monitoring at conservation and tourist areas. This study provides detailed knowledge of roaring activity of male Far-East wapiti (Cervus elaphus xanthopygus) in the rut period of 2017 at three sites of most active rut at the 453.4 km2 territory of the State Nature Reserve «Bolshekhekhtsirsky» (Far East of Russia). Rutting calls were recorded for 5 min/h throughout the 58-day rut period by using three automated recording devices, one in each site, with simultaneous registration of temperature, once per hour. In total, we recorded 3474 rutting calls (1538, 1159 and 777 calls in the three sites respectively). In each site, the roaring activity (calculated as the mean daily number of calls/h) demonstrated a similar dynamic of three rut phases: start phase, active phase and fading phase. Although the roaring activity displayed a positive correlation between sites, the actual values of the mean number of calls/h differed between sites. This finding indicates the different use of the three sites by males during the rut. At any site, the roaring activity was related to time of day (hourly); it was the highest between 03:00 a.m. and 06:00 a.m. and nearly lacked between 10:00 a.m. and 6:00 p.m. At any site, the number of calls/h increased steadily from 8:00 p.m. to 03:00 a.m. to a maximum value and then rapidly decreased from 06:00 to 09:00 a.m. to a minimum value. The effect of temperature on the daily and hourly roaring activity was weaker than the effect of time of day. We discuss the results with similar data of another protected Russian population of Far-East wapiti inhabiting the State Nature Reserve «Ussuriysky».