Kea (Nestor notabilis), along with the kaka (Nestor meridionalis) and the kakapo (Strigops habroptilus), together form the living members of a distinct parrot family, Strigopidae, within the avian order Psittaciformes [parrots and cockatoos]. It seems likely that the Strigopidae lineage diverged from those of other parrots some 85 – 55 million years ago, perhaps as a result of geographical isolation following separation of the microcontinent ‘Zealandia’ (the precursor to present-day New Zealand) from Gondwana.
Recent molecular genetic evidence places the divergence of the Strigops and Nestor lineages at some 30 million years ago, coinciding with the possible submergence of Zealandia when much of the land mass may have been fragmented into small islands. Finally, divergence of the Nestor genus into the kea and kaka forms that we know today probably occurred some 1 – 4 million years ago possibly in response to the repeated glacial periods of the ‘ice ages’ and the tectonic mountain uplifting which created the Southern Alps.
Thus it appears that the evolution of the Strigopidae family is a valuable legacy of the dramatic geological changes that Zealandia / New Zealand has experienced since a distant time when a kaka-like bird may have foraged in trees above the heads of dinosaurs. These days kaka typically inhabit lowland forests and feed predominantly on seeds and fruits while kea are a more generalist species adapted to living on a diverse range of foods in a more harsh mountain environment.
Species Nestor notabilis