The baroque potheads: Modification and embellishment in repeated call sequences of long-finned pilot whales

Vocal variation within calls that are generally stereotyped suggests multiple simultaneous functions. These vocal cues may be especially important for group-living species. We describe two fundamental call transition types within repeated call sequences of long-finned pilot whales (Globicephala melas): embellishment-discrete changes to a specific part of a call-and morphing- non-discrete small changes across a call. Of transitions between consecutive calls, 31% were embellished and 20% morphed. Modifications between pairs of consecutive calls were often followed by another modification of the same type, with sequences of embellished transitions generally alternating between ornamentation and simplification. Ten classes of embellishment varied in rate of occurrence as well as temporal location within a call. Most common were the addition/deletion of pulsed or tonal elements. Functions of these modifications could include conveying information on location or the emotional state of the signaller, or they could be products of vocal innovation.