Singing in unison: duets and choruses in Blue Manakins (Chiroxiphia caudata)

Acoustic signals are widespread in several animals and evolved as an important communication channel. Here, we studied sounds produced by blue manakins (Chiroxiphia caudata) and described its acoustic repertoire. We tested if our description based on visual inspection of spectrograms can be discriminated by five acoustic parameters of frequency (kHz) and time. We also described for the first time a synchronized vocal behavior in this species produced prior to the cooperative dance of males in lek areas. We classified and quantified the synchronization type and rate of this sound production. We recorded vocalizations and behavioral data at Mananciais da Serra Protected Area (Piraquara-PR), Brazil, and performed a linear discriminant analysis after extracting their acoustic parameters. We described ten vocalizations associated with eight behaviors and synchronized sounds, i.e. “duets” and “choruses”. Differently from other congeners, we found a large variation in this behavior. Synchronizations were antiphonal, overlapped or both and males also varied on the quantity of vocalizations emitted per bouts, ranging from two to 13 notes of three types in a sequence (3.3±1.84, n=141). Our study provided evidence that, within all Pipridae species, choruses are exclusive of blue manakins since two or more males can perform this behavior together. Although it is not clear how males choose their partners to perform together due to variation on the identity of males attending display courts, the high variation found in duets/choruses suggests that synchronization is an important factor in female attraction.