Sex and Age-class Differences in Vocalizations of Roosevelt Elk During Rut

Abstract

Vocalizations of free-ranging Roosevelt elk (Cervus elaphus roosevelti) were studied at Gold Bluffs Beach, Prairie Creek Redwoods State Park, Humboldt Co., California, from August through November 1973. Significant differences were found in types and rates of elk vocalizations among different sex and age classes. Bull vocalizations varied with age and social status. Sonograph analyses revealed structural similarities in elk cohesion calls, bugles and yelps; bugles and yelps may be elaborations of cohesion calls. Bugling and yelping by master bulls occurred primarily in male-female encounters and may have functioned to bring cows closer together; bulls bugled most often when the harem was widely dispersed. Bulls vocalized less frequently in aggressive interactions between bulls where bugling and yelping clearly were related to male dominance. INTRODUCTION Despite extensive literature concerning mammalian vocalizations (Marler, 1955, 1967; Collias, 1960; Sebeok, 1968; Tembrock, 1968), comparatively little information exists for ungulates. Much of the recent literature on ungulate vocalizations was summarized by Kiley (1972), but quantitative descriptions of vocalizations and data on their causation were presented primarily for domestic species. Further, quantitative research on wild species often has focused on alarm vocalizations (Hirth and McCullough, 1977; Yahner, 1980; Richardson et al., 1983) or calls between mother and young (Espmark, 1971, 1975). Types and variability of vocalizations in other subspecies of Cervus elaphus have been well-documented (Murie, 1932, 1951; Darling, 1937; Johnson, 1951; Ahlen, 1965; Bubenik and Brna, 1967; Harper et al., 1967; Struhsaker, 1967; Olsen, 1979), and Peters (1980) reviewed the vocalizations of North American elk. Data on vocalizations of Roosevelt elk (C. e. roosevelti), however, were limited to qualitative descriptions (Graf, 1955; Harper et al., 1967), and information on the function and circumstances under which these sounds occurred was lacking. Further, Clutton-Brock and Albon (1979) noted that roaring by red deer (C. e. scoticus) stags occurred primarily during aggressive interactions between males, but roaring also was directed toward females in the stag's harem, suggesting a male-female function for this vocalization. Miura (1984) also noted that bugle-like moans of male sika (Cervus nippon) were given in response to the activities of females. The purpose of this study was to quantifv sex and age-class differences in vocalizations from a free-ranging population of Roosevelt elk during rut, and to examine the behavioral context in which vocalizations occurred. 'Present address: Institute of Arctic Biology, and Department of Biology and Wildlife, 211 Irving Building, University of Alaska, Fairbanks, Alaska 99775-1780.