Data from: Vocal characteristics of distress and reproductive vocalizations in North American wapiti

Variation in the vocal behavior of nonhuman vertebrates includes graded
transitions and more dramatic changes. Wapiti males produce a reproductive
bugle that has a fundamental frequency that surpasses 2,000 Hz with
evidence of biphonation and other nonlinear phenomena. Here, we analyse
the acoustic structure of captive wapiti vocalizations to compare the male
bugle with three categories of distress vocalizations: neonate distress
(capture) calls, calf isolation calls, and adult female isolation calls.
These four high-arousal call categories serve a common general function in
recruiting conspecifics but occur in different behavioural contexts
(capture, isolation, reproduction). Our goal was to distinguish
characteristics that vary in graded steps that may correspond to an
animal’s age or size from characteristics that are unique to the bugle.
Characteristics of the high and loud fundamental (G0) varied in an
age/size-graded manner with a decrease in minimum G0, an increase in the
maximum and range of G0, with no evidence of sex differences. The
nonlinear phenomena of deterministic chaos, biphonation, and frequency
jumps were present in all four call categories and became more common from
the distress vocalizations of neonates to calves to adult females to the
male bugle. Two temporal characteristics sharply distinguished the bugle
from the three categories of distress vocalizations: these included a
prolonged call duration and a maximum G0 that occurred much later in the
call for the bugle than for distress vocalizations. Our results suggest
that distress vocalizations of different age groups and the reproductive
bugle of wapiti share a high G0, with age/size-graded changes in G0 and
nonlinear phenomena, but differ sharply in temporal characteristics.