Hybrid zones and cultural traits of the Australian ringneckPlatycercus zonarius

Abstract

Two hybrid zones between subspecies of the Australian ringneck parrot (Psittacidae:Platycercus zonarius) were examined for morphological (plumage patterns) and cultural (learned contact flight calls) traits. Mensural traits and plumage patterns also were quantified in a study in the 1960s. My samples were taken from populations in the allopatric distributions of the parental taxaP. z. zonarius(Port Lincoln parrot),P. z. semitorquatus(twenty‐eight parrot), andP. z. barnardi(Mallee ringneck) and within the hybrid zones. The two hybrid zones differed in the distribution of plumage patterns: (a) in thezonarius – semitorquatuszone of intergradation all sample locations comprised birds of both subspecies’ plumage patterns as well as numerous birds in hybrid plumage and (b) in thezonarius – barnardizone of intergradation all birds were in hybrid plumage. The cultural trait also differed in the two hybrid zones: the acoustic features ofP. z. zonariusflight call predominated in the birds in the hybrid zone withP. z. semitorquatus, regardless of plumage displayed by the individuals; whereas in theP. z. zonarius – P. z. barnardizone of hybridization the acoustic features of theP. z. barnardiflight call notes evidently have swamped out those ofP. z. zonarius. The results on the cultural trait reject ‘coexistence’ and ‘blending’ models of cultural interchange but support a ‘cultural dominance’ model. Hypotheses are discussed concerning historical and behavioral means by which the patterns arise.