The North Island Takah? or M?ho, Porphyrio mantelli, is an extinct rail that was found in the North Island of New Zealand. This flightless species is known from subfossils from a number of archeological sites and from one possible 1894 record (Phillipps, 1959).
The decline of the species has generally been attributed to the increasing incursion of forest into the alpine grasslands through the Holocene, although hunting by the M?ori probably also played a role.
Traditionally the North Island Takah? was considered conspecific with the threatened South Island Takahe P. hochstetteri. Trewick (1996) presented evidence that the two taxa were independently derived from flying ancestors, so proved to be separate species.
The binomial of this bird commemorates the naturalist and civil servant Walter Mantell.