The New Zealand dotterel is a familiar bird of sandy east coast beaches in the northern North Island, but is sparsely distributed around much of the rest of the country. There are two widely separated subspecies: the northern New Zealand dotterel is more numerous, and breeds around the North Island; the southern New Zealand dotterel was formerly widespread in the South Island, and now breeds only on Stewart Island. Southern New Zealand dotterels are larger, heavier, and darker than northern New Zealand dotterels.
Ref:  Birds Online (NZ Dotterel)