Data from: Social group signatures in hummingbird displays provide evidence of co-occurrence of vocal and visual learning

Vocal learning, in which animals modify their vocalizations based on
social experience, has evolved in several lineages of mammals and birds,
including humans. Despite much attention, the question of how this key
cognitive trait has evolved remains unanswered. The motor theory for the
origin of vocal learning posits that neural centers specialized for vocal
learning arose from adjacent areas in the brain devoted to general motor
learning. One prediction of this hypothesis is that visual displays that
rely on complex motor patterns may also be learned in taxa with vocal
learning. While learning of both spoken and gestural languages is
well-documented in humans, the occurrence of learned visual displays has
rarely been examined in non-human animals. We tested for geographic
variation consistent with learning of visual displays in long-billed
hermits (Phaethornis longirostris), a lek-mating hummingbird that, like
humans, has both learned vocalizations and elaborate visual displays. We
found lek-level signatures in both vocal parameters and visual display
features, including element proportions, sequence syntax, and fine-scale
parameters of elements. This variation was not associated with genetic
differentiation between leks. In the absence of genetic differences,
geographic variation in vocal signals at small scales is most
parsimoniously attributed to learning, suggesting a significant role of
social learning in visual display ontogeny. The co-occurrence of learning
in vocal and visual displays would be consistent with a parallel evolution
of these two signal modalities in this species.