PARENT SESSION

Behavior 3 -- Session Chair: Sacha Vignieri-- Nelson Hall East, Goodwin Forum

WAPITI BUGLES: FORM, SIGNATURE AND HONEST SIGNALING. Jennifer Johnson and Jennifer Clarke. Dept. of Biological Sciences, University of Northern Colorado, Greeley, CO, USA.

ABSTRACT- We measured the form of male wapiti (Cervus elaphus) bugle calls emitted during the breeding season to investigate two hypotheses: 1) that individual variation exists in acoustic characteristics of this call and 2) that acoustic characteristics of the bugle are related to physical attributes of the vocalizing male. We measured 144 bugles from 14 male wapiti (>6 bugles/male) in a wild population in Rocky Mountain National Park, Colorado, USA, during two breeding seasons (1998 and 1999). Signature characteristics were evident regarding: a) frequency (kHz) with maximum power (db) in the bugle (p <0.01) and b) frequency (kHz) with maximum power (db) in the whistle segment (p <0.01). Male wapiti also exhibited individually unique signature frequency modulations in different segments of their bugles. Male wapiti exhibited unique signature characteristics in the stereotypic bugle call, but not unique signature calls. Wapiti with the largest antlers (a relative indication of size/health/maturity) also had the greatest range of powerful frequencies in the same bugle (p< 0.001), which we termed the Pavarotti Effect (after the range of Italian tenor, Luciano Pavarotti). Thus, the wapiti bugle appears to be an honest signal, which is a signal that conveys accurate information. These Pavarotti males also had the largest herds (p< 0.02), indicating they may have greater potential fitness. The male wapiti bugle strongly differs from the roar emitted during the breeding season by the European C. elaphus, red deer, regarding the acoustic parameters associated with signature characteristics and honest signalling. These vocalization differences may be linked to selective pressures on propagation efficiency in the different environments that these ungulates inhabited prior to human habitat modification.

KEY WORDS: communication, signature, Cervus, elk