Dataset for: Body size and sexual selection shaped the evolution of parrot calls

Morphology, habitat and various selective pressures (e.g., social and
sexual selection) can influence the evolution of acoustic signals, but the
relative importance of their effects is not well understood. The order
Psittaciformes (parrots, sensu lato) is a large clade of very vocal and
often gregarious species for which large-scale comparative studies of
vocalizations are lacking. We measured acoustic traits (duration, sound
frequency, frequency bandwidth and sound entropy) of the predominant call
type for >200 parrot species to test: (1) for associations with
body size; (2) the acoustic adaptation hypothesis (predicting differences
between forest and open-habitat species); (3) the social complexity
hypothesis (predicting more complex calls in gregarious species); and (4)
influences of sexual selection (predicting correlated evolution with
colour ornamentation). Larger species had on average longer calls, lower
sound frequency and wider frequency bandwidth. These associations with
body size are all predicted by physical principles of sound production. We
found no evidence for the acoustic adaptation and social complexity
hypotheses, but perhaps social complexity is associated with vocal traits
not studied here, such as call repertoire sizes. More sexually dichromatic
species had on average simpler calls (shorter, with lower entropy and
narrower frequency bandwidth) indicating an influence of sexual selection,
namely an evolutionary negative correlation between colour ornamentation
and elaborate acoustic signals, as predicted by the transference
hypothesis. Our study is the first large-scale attempt at understanding
acoustic diversity across the Psittaciformes, and indicates that body size
and sexual selection influenced the evolution of species differences in
vocal signals.