117 Origin of New Zealand Parrots

Key Idea: The kakapo, kea, and kaka evolved from an ancestor that lived around 80 mya. The rise of the Southern Alps provided new habitat occupied by the ancestor of the kea. Recent mitochondrial DNA (mtDNA) studies at Victoria University confirm the existence in New Zealand of two distinct groups of parrots: kakapo-kaka-kea, and the various kakariki (5 species). This research provides an excellent example of the use of DNA analysis to determine evolutionary relationships. The kakapo-kaka-kea group originated from an unknown Australian ancestor about 100 mya. The origin of this proto-kaka/kakapo was associated with the break-up of Gondwana and formation of the Tasman Sea, when New Zealand moved away from Australia and became isolated. The kakapo split from this lineage 60-80 mya and is our most ancient parrot. Kaka split from the kea line some 3 mya and an early member migrated to produce the now-extinct Norfolk Island kaka. About 400,000 years ago the North and South Island kaka differentiated.

Geological event Speciation event

CC 2.0 Rosino

Kaka (Nestor meridionalis) has a North Island and a South Island subspecies. They feed on fruit, honeydew, and insects.

Kea (Nestor notabilis) inhabits mountain regions of the South Island. They feed on fruit and insects, and are also scavengers. Kakapo Kea Norfolk Island kaka (extinct) North Island kaka South Island kaka

Low sea level during glacials. Isolation of the North Island from the South Island by the formation of Cook Strait.

Kaka

Vicariance: kaka splits into the North Island and South Island sub-species about 0.4 mya.

The Southern Alps begin to rise around 5 mya. Formation of the Manawatu Strait splits New Zealand.

Proto-kaka

The new alpine environment allows the ecological divergence of the kaka and the kea from the proto-kaka about 3 mya.

Australia and New Zealand become separated by the formation of the Tasman Sea about 80 mya.

DoC-RM

Kakapo (Strigops habroptilus) is a ground-dwelling (flightless) night parrot that was once widely distributed throughout Fiordland and Stewart Island. They feed on berry fruit. Beginning of the break-up of the Gondwana segment containing New Zealand about 100 mya.

Source: E.J. Grant-Mackie (Thames High School) and J.A. Grant-Mackie (Geology Dept, University of Auckland), based on mDNA studies by Prof. Geoff Chambers and Dr Wee Ming Boon (Victoria University, Wellington).

Protokaka/kakapo

Australian ancestor (unknown)

New Zealand is well-forested 60-80 mya, allowing the ecological divergence of the proto-kaka and kakapo into tree-dwelling and ground-dwelling types.

Vicariance: Unknown Australian ancestor gives rise to the proto-kaka/kakapo group about 100 mya. Vicariance is a term to describe the geographical separation of a population. It has been important to speciation events in New Zealand.

Australia

Tasman Sea

New Zealand

Kaka

Manawatu Strait . North Is. kaka

Separation from Australia

Australia and New Zealand are separated by the formation of the Tasman Sea 80 mya

Forest

Tundra

Alpine scrub Kaka and kakapo Kea

Late Miocene

Period warmer than today 10 mya

Early Pleistocene

Glaciation ~ 2.5 mya Kea

. South Is. kaka

Holocene

Warm interglacial today

1. What role did geographical isolation play in the divergence of the proto-kaka/kakapo from its Australian ancestor?

2. (a) Describe the two habitats in which the kaka and kea species evolved:

(b) When did these two different habitats emerge?

(c) How could the kaka and the kea have evolved from an ancestral proto-kaka?

3. Identify the species that became cold-adapted:

4. Why do the modern kaka and kea species in the South Island not interbreed?

5. It has previously been postulated that the kakapo may be related to the Australian night parrots and/or Australian ground parrots, but this has not been supported by modern DNA studies. Suggest a reason for the similarities (appearance, ground nesting, poor flight) between these Australian parrots and the kakapo:

6. The kakapo is described as our most ancient parrot. Why do they deserve this label?