Vocal learning in birds is typically restricted to a sensitive period early in life, with the few exceptions to this rule reported in songbirds and parrots. Here we present evidence of open-ended voca
Producing a specific number of vocalizations with purpose requires a sophisticated combination of numerical abilities and vocal control. Whether any animal possesses such a capacity to voluntarily con
Learned vocalizations play a key role in parrot social dynamics and vocal dialects have been documented for several mainland species, but to date no studies of geographically structured call variation
