The Takahe (Notornis mantelli Owen, 1848): A General Survey By G R Williams, Wildlife Service, Department of Internal Affairs* Since this paper was written Mr. Williams. has transferred to the staff of Lincoln College, Christchurch—Editor. [Communicated by E. G. Turbott, and read before the Royal Society of New Zealand, Canterbury Branch, August 8, 1959, received by the Editor, September 29, 1959.] Abstract An account is given of the history, classification and description of Notornis mantelli Owen (Aves: Rallidae). As it is monomorphic, sexes are determined in the living bird by using a combination of weight and culmen measurements. Plumage sequences are outlined. After describing the present habitat there is a discussion of changes in distribution and their possible causes. Long-term climatic changes are considered the most important of these. Following sections deal with food and feeding habits, calls, display, pair bonds and territorial behaviour. Banding studies show that pair bonds probably last for life and that territory is held throughout the year and usually for a number of years—if not for life also. Aspects of breeding biology dealt with are: breeding age (known to be at one year for at least one bird), length of breeding season, nesting behaviour, clutch size (1 or 2 eggs), re-nesting, incubation (shared by both sexes, period approximately 28 days) and egg fertility (at least 75%). Aspects of population ecology discussed are: embryo survival and hatching success (57% for the latter), chick production (0. 25 to 0. 45 per adult to the stage of leaving the nest), juvenile and adult mortality (provisional estimates are given) and population size and its regulation. Territorial behaviour limits population density but not, apparently, through the food value of the territory. The size of the territory seems to be governed mainly by what is here called “acquisitiveness” rather than being closely correlated with any obvious requisite in the environment. This view of territorial behaviour is briefly discussed. General History. The rediscovery of a colony of this large, flightless rail in 1948, on the western side of Lake Te Anau, in the South Island, caused interest throughout the world; and the flavour of the excitement of that time appears strongly in the discoverer's account (Orbell, 1949). The find was a most unexpected one for, in the century before, only five recent specimens had come to light and, as 50 years had passed since the last, the species was regarded as extinct. Brief histories of these specimens and of the subfossil type of the extinct North Island race are given in the table: Table No. I. Discovery Date Place Described by Comments 1847 Waingongoro R., Taranaki, N. I. Owen, 1848a and b In British Museum (Nat. Hist.). Type N. m. mantelli 1849 Dusky Sound, S. I. Mantell, 1850 In British Museum (Nat. Hist.) 1851 Deas Cove, Thompson Sound, S. I. Buller, 1873 (mention only) In Dominion Museum, Wellington. Formerly in B. M. (N. H.) 1879 Nine miles S. E. of Lake Te Anau, S. I. Meyer. 1883 Dresden Museum (now destroyed—Steinbacher, 1949). Type N. m. hochstetteri. 1884 Patience Bay. Lake Te Anau, S. I. Parker. 1886 Skeleton only, in Otago Museum. Dunedin. 1898 Middle Fiord of L. Te Anau, S. I. Benham. 1899a, b and c In Otago Museum, Dunedin.