The variable oystercatcher, or tōrea pango, is a striking black or black-and-white shorebird with a long, bright orange bill. Found along New Zealand’s coasts, they use their strong beaks to feed on shellfish and other invertebrates. Once rare due to hunting, their numbers have slowly recovered under protection. The total population is estimated at 5000-6000; however, there has been no surveys since the 1990s.
The existence of different colour morphs (black, intermediate or ‘smudgy’, and pied) caused early confusion, and they were variously thought to be different species, forms, or hybrids. This confusion was compounded by a cline in morphs, with the proportion of all-black birds increasing from north to south. Pied morph birds can be confused with South Island pied oystercatcher. If seen together, adult variable oystercatchers are noticeably larger and the demarcation between black and white on the breast is generally sharper on South Island pied.
Source: https://www.nzbirdsonline.org.nz/species/variable-oystercatcher