[3] These color differences are attributed to the latitude of the habitat, where the northernmost oystercatchers have significantly more white on their bodies than those of southern origin.

Similar to a needle in shape, the bill is thin and long, and darkens to a deep red color during the breeding season.

[citation needed] Length of individuals range from 42 to 47 cm from beak to tail and have a short, sturdy body with a thick neck.

The variable species has less definition between the black and the white area, as well as a mottled band on the leading edges of the underwing.

Variables also have a smaller white rump patch which is only a band across the base of the tail rather than a wide wedge shape reaching up to the middle of the back as in the SIPO.

While both sexes have the same plumage colorations and appear visually similar, there is some body dimorphism and female oystercatchers tend to be slightly larger in size.

[8] The species has likely remained endemic due to its sedentary lifestyle and lack of migration, keeping all populations within the same island habitat.

[9] While they occur in lower densities on the western coastlines they are concentrated in these areas; Northland, Coromandel Peninsula, Bay of Plenty, Greater Wellington, Nelson/Marlborough and Fiordland.

[11] Individuals have been known to congregate in short grassed paddocks and sometimes forage in pastures after rain however will generally remain around the coastal beaches, estuaries and shorelines.

These movements are also used to distinguish territory space outside of the mating season, when the adult birds prefer living in solitary environments.

After a female has decided to breed with a male, the pair remains monogamous during the rest of the mating season and potentially for several consecutive years thereafter.

[12] By the beginning of their first fall season, usually early August, the young leave their parent's care and join other juveniles to form a loose flock.

[8][12][4] While no conservation efforts are in effect, other pieces of legislation that protect threatened and endangered coastal birds provide some additional resources for the oystercatchers as well.

[11] Habitat loss such as decreasing coastal dunes that provide essential breeding locations for the species are likely to have a large impact on all populations.

[16] These parasites do not harm the host, and are expected to simply consume a small supply of resources that the bird intakes.