Note the black tail; the scientific name translates to Black-tailed Flower-Bird. This is an adult male. Females are duller and have a yellowish cheek stripe. Immatures are similar but have brown rather than red eyes. The genus Anthorinis is endemic to New Zealand and the Bellbird is the only extant species in its genus. Widespread in NZ, the species reaches the southernmost limit of its range in the Auckland Islands. They are in the Honeyeater family, part of a group of nectar specialists; but this species also eats fruit and insects. It is unrelated to the New World Bellbirds which are in the Cotinga family or to the Australian Bellbirds which are in the Oreoicidae (Australo-Papuan Bellbirds). Canon PowerShot SX50 HS.
References:
Higgins, P., Christidis, L. & Ford, H. (2017). New Zealand Bellbird (Anthornis melanura). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/60267 on 27 February 2017).
Higgins, P.J.; Peter, J.M.; Steele, W.K. 2001. Handbook of Australian, New Zealand and Antarctic birds. Vol. 5, tyrant-flycatchers to chats. Oxford University Press, Melbourne.
Shirihai, H. (2007) A Complete Guide to Antarctic Wildlife. The Birds and Marine Mammals of the Antarctic Continent and the Southern Ocean. 2nd edition. A&C Black, London.
Sagar, P.M. 2013. Bellbird. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz