Rutting calls of harem-holders, harem-candidates and peripheral male Siberian wapiti Cervus canadensis sibiricus: Acoustic correlates of stag quality and individual identity

Abstract

This study investigates the effects of individuality and harem-holding status on the acoustic parameters of rutting calls (bugles) of 14 stags of Siberian wapiti Cervus canadensis sibiricus. The stags competed for mating with hinds in a large herd, free ranging inside a fenced area with complex landscape. We considered as harem-holders the stags, which kept a harem of 5 or more hinds for at least 2 days. Of the 15 days of observations enveloping the most active rutting period, during 3 days there was only one harem in the enclosure, during 9 days two harems, during 2 days three harems and during 1 day four harems. Stag bugles displayed both individual and status-related variation. Harem-holders compared with peripheral stags had shorter bugles with higher minimum fundamental frequency. After winning a harem and changing status from harem-candidate to harem-holder, stags shortened the duration of their bugles, lowered the beginning and maximum fundamental frequency and increased the minimum fundamental frequency. Significantly higher than the levels expected by chance, discriminant analysis classified 78.9% of bugles by the correct stag status and 53.2% of bugles by the correct individual callers. Different acoustic parameters encoded the status and individuality of the bugles. Status was encoded by the duration of the start and end parts and by the beginning and end fundamental frequencies. Individuality was encoded by the maximum fundamental frequency. We discuss that rutting calls of Siberian wapiti, although individualized, do not represent vocal signatures. However, these calls reliably mark stag harem-holding status.