The pale streaking within the dark areas of the head and body characterize the Stewart Island subspecies (P. a. rakiura). In this respect, it more closely resembles the North Island Robin (Petroica longipes) than it does the geographically closer South Island Robin (Petroica australis). P. a. rakiura also has more extensive white underparts than either species. These confiding birds often perch on a vertical trunk or stem as seen here. This species was reintroduced to Ulva Island after the island was rid of introduced predators. Here it can be found nesting mostly in broad-leaved coastal vegetation.
Following a recommendation by Miller & Lambert and others, the New Zealand Checklist splits the New Zealand Robin into two species, North Island Robin and South Island Robin, the latter with two subspecies. Under this taxonomy, our bird is a "South Island Robin" with the nominate race occurring on South Island while P. a. rakiura is on Stewart Island. This split has been adopted by IOC and H&M4 but not by Clements/eBird nor by HBW.
The name "rakiura" is Maori for Stewart Island. It means glowing skies in reference to the aurora australis or southern lights.