ANALYSIS OF A CULTURAL TRAIT ACROSS AN AVIAN HYBRID ZONE: GEOGRAPHIC VARIATION IN PLUMAGE MORPHOLOGY AND VOCAL TRAITS IN THE AUSTRALIAN RINGNECK PARROT (PLATYCERCUS ZONARIUS).

The article discusses a study that analyses the vocal signals of Australian Ringneck Parrots or Platycercus zonarius and their covariation geographically with morphology. It states that the study considered 398 birds in a hybrid zone in Western Australia wherein plumage traits and vocal calls were recorded. The article explains that the vocal signals are functions of parental taxa and introgressive hybridization that suggests a theory of cultural dominance. According to the article, the flight call can be traced back to the Pleistocene period.