Two subspecies are recognized. This is C. b. exilis, a bird of extremely limited range found only on Enderby and Adams Islands in the Auckland group where it is resident. It was first described by Falla in 1978. It is larger, paler and has longer legs than nominate. Its chest bands are also less distinct and flecked with white. The smaller nominate race breeds on Chatham and the main New Zealand Islands. Most of them migrate to Tasmania and southeastern Australia; an unusual east-west migration.