“Thus, I have been using yellow-naped amazons as a model to study complex parrot vocal signals in the wild. The warble duets, which I researched for this study, are their most complex signal,” Dahlin tells Popular Science. Yellow-naped amazons (Amazona auropalliata) are highly social yellow-green parrots found in Central America. The team studied the duets with a text-analysis software called Voyant and found that the yellow-naped amazons’ duets have 36 call types, making up a large lexicon, or vocabulary. “It is vital that yellow-naped amazons are allowed to breed in peace, that people appreciate them in their natural environment, and not try to capture them for pets.”