Wrybill breed on large braided rivers in central South Island from August-January. They prefer large dynamic rivers that will not become overgrown with weeds. Once prevalent on smaller rivers, the wrybill’s range as contracted to about 60% of its estimated original habitat (distribution map).
The wrybill or ngutuparore (Māori) Anarhynchus frontalis is a species of plover endemic to New Zealand. It is unique in that it is the only species of bird in the world with an asymmetrically bent bill, which it uses to dig around river stones for freshwater invertebrates. Measuring 20–21cm long and weighing between 43–71gm, the wrybill is slightly sexually dimorphic. The most distinctive feature of the bird is the long black bill, which is always curved to the right.
The male has a white forehead and pale grey crown, nape, back, wings and tail and a white throat, breast, belly and rump, with a thin black band across the breast. This band is thinner in the female, and much less distinct in both sexes in the non-breeding season. Males have a small black bar between the white forehead and the grey crown. As with the breast band, this is reduced in the non-breeding season.
Their eggs are blue-grey and lightly speckled, making them well camouflaged against river stones and pebbles, which generally make up the main structure of a very simple nest.