Roaring High and Low: Composition and Possible Functions of the Iberian Stag's Vocal Repertoire

Abstract

We provide a detailed description of the rutting vocalisations of free-ranging male Iberian deer (Cervus elaphus hispanicus, Hilzheimer 1909), a geographically isolated and morphologically differentiated subspecies of red deer Cervus elaphus. We combine spectrographic examinations, spectral analyses and automated classifications to identify different call types, and compare the composition of the vocal repertoire with that of other red deer subspecies.Iberian stags give bouts of roars (and more rarely, short series of barks) that are typically composed of two different types of calls. Long Common Roars are mostly given at the beginning or at the end of the bout, and are characterised by a high fundamental frequency (F0) resulting in poorly defined formant frequencies but a relatively high amplitude. In contrast, Short Common Roars are typically given in the middle or at the end of the bout, and are characterised by a lower F0 resulting in relatively well defined vocal tract resonances, but low amplitude. While we did not identify entirely Harsh Roars (as described in the Scottish red deer subspecies (Cervus elaphus scoticus)), a small percentage of Long Common Roars contained segments of deterministic chaos.We suggest that the evolution of two clearly distinct types of Common Roars may reflect divergent selection pressures favouring either vocal efficiency in high pitched roars or the communication of body size in low-pitched, high spectral density roars highlighting vocal tract resonances. The clear divergence of the Iberian red deer vocal repertoire from those of other documented European red deer populations reinforces the status of this geographical variant as a distinct subspecies.

Iberian red deer: paraphyletic nature at mtDNAbut nuclear markers support its genetic identity

“…; Passilongo et al. ) and anatomy (Frey et al. ), microsatellite data support the idea of a homogeneous Iberian red deer group.…”

“…), and acoustic features of male roars (Passilongo et al. ). These similarities might have arisen by phenotypic plasticity (Geist ) or by evolutionary convergence (see Duarte et al.…”

Evidence of biphonation and source–filter interactions in the bugles of male North American wapiti (Cervus canadensis)

“…Red: maximal compression closes the slit and leaves only a small ventral opening (∼2 mm in diameter). Rostrodorsal view, compression by plastic strap (not visible distance; and longer, higher-pitched and higher-amplitude common roars, which may advertise stamina and presence over longer distances (Passilongo et al, 2013). This illustrates how different species have evolved different solutions to the challenge of producing signals that are characterised by a dense spectrum (low F0) and a high amplitude (high G0) with the relatively small larynges of terrestrial mammals.…”

The unique Mesola red deer of Italy: taxonomic recognition (Cervus elaphus italicusnova ssp., Cervidae) would endorse conservation#

“…High nutrition plane experiments will permit us to fully test the potential of this population in terms of body size and growth. The study of vocal characteristics of roars and the comparison with other European populations could help to further elucidate its taxonomic status, as tested in the Tyrrhenian and Iberian red deer (Kidjo et al 2008;Frey et al 2012;Passilongo et al 2013), although the phenology of animal vocalisations is also influenced by the habitat where they have lived.…”