Duets in Yellow‐Naped Amazons: Variation in Syntax, Note Composition and Phonology at Different Levels of Social Organization

Abstract

Complex vocal signals composed of multiple notes are used by many species. Such signals may vary in a number of features such as the rules that govern note order and timing (syntax), the relative number and types of different notes (note composition), and the acoustic structure of notes (phonology). Previous research examining male song in songbirds typically has shown greater conservation of syntax than phonology. Here we investigated whether these patterns of variation are also found in the duets of parrots. We examined geographic variation in the pair duets of yellow‐naped amazons, Amazona auropalliata, at five sites within one vocal dialect. We also examined variation at several levels of social organization, including within pairs, among pairs and among sites, to assess where variability was greatest. Variation was highest at the within‐pair level, although variation was also present at all other levels and for all of the duet factors. We hypothesize that variation at the among‐site level allows duets to indicate site membership, while variation at the within‐pair level allows pairs to change their duet to match their current social or physical environment. Syntax and phonology are also more conserved than note composition for all levels of social organization. This pattern may result because note composition is less important in duet function than syntax or phonology, or because development of syntax and phonology is more heavily influenced by genetic templates.

Vocal dialects in parrots: patterns and processes of cultural evolution

“…The Palm Cockatoo, Probosciger aterrimus , and Yellow-naped Amazon have call repertoires with distinct dialectal regions; in both these species several different call types vary at the same boundaries (Dahlin and Wright 2009; Keighley et al 2017; Wright 1996). In the Eastern Ground Parrot, Pezoporus wallicus wallicus , some call types in the repertoire are shared between geographic areas while others are unique (Chan and Mudie 2004).…”

Duet Function in the Yellow‐Naped Amazon, Amazona auropalliata: Evidence From Playbacks of Duets and Solos

“…We created duet exemplars using duets from 16 pairs of yellow-naped amazons recorded in 2002 and 2006 at Ahogados, Horizontes and Santa Rosa. Detailed analyses of the structure of duets from 1995 and 2002 confirm that duet form is temporally stable over multiple years (Dahlin & Wright 2009; Wright & Dahlin 2007) as is territory maintenance by specific pairs (Dahlin and Wright, unpublished data). We digitized calls by playing video tapes on a SONY Hi-8 player (model GVD-200), running the sound through an i-Mic (Griffin Technology) into a Macintosh Power PC G5 computer and digitizing at 44 kHz and 16 bits in Raven 1.2.1 (Cornell Lab of Ornithology).…”

“…We created spectrograms in Raven following Dahlin and Wright (2009). We scored calls as male and female by following previously defined syntactical rules (Dahlin & Wright 2009; Wright & Dahlin 2007; Wright & Dorin 2001). We amplified calls when necessary to standardize the peak amplitude of duets and solos.…”

“…The yellow-naped amazon, Amazona auropalliata , is an ideal species for the purpose of investigating the joint territory defense and mate-guarding hypotheses as they give complex vocal duets at nesting territories that are maintained throughout the year (Dahlin & Wright 2009; Wright & Dahlin 2007; Wright & Dorin 2001). Parrots also represent a novel group for the study of duets.…”

“…Calls given outside duets do not appear to be sex specific (Dahlin and Wright unpublished data). Duets have a number of syntactic rules that organize the timing and structure of calls, but within those constraints, duets vary in length and note composition both within and between pairs (Dahlin & Wright 2009; Wright & Dahlin 2007). Pairs give duets year-round, although rates are highest in January and February, at the beginning of the nesting season (Dahlin and Wright unpublished data).…”