Unlike its close relative, the North Island kōkako (C. wilsoni), it has largely orange wattles, with only a small patch of blue at the base, and was also known as the orange-wattled crow (though it was not a corvid).

The South Island kōkako was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

Early explorer Charlie Douglas described the South Island kōkako call: "Their notes are very few, but the sweetest and most mellow toned I ever heard a bird produce.

[3] Unconfirmed sightings of South Island kōkako and reports of calls have continued,[18][19][20][21] but no authenticated recent remains, feathers, droppings, video, or photographs exist.

[22] A potential kōkako call, consisting of a "a distinct couple of soft long notes" was recorded at Heaphy Track on 29 December 2021, followed by a sighting of "a bird of the right size and colour".

Their public search campaign, launched in January 2017 and with over 430 reports of possible encounters to February 2024, has a $10,000 reward on offer for evidence, likely a photograph or video, which would need to be verified by the Dept of Conservation and Birds NZ.