This is an immature. Females and immatures lack the male's red color and are streaked with brown. Lesser Redpolls average smaller and darker with less prominent wing-bars than Common Redpolls but there is considerable variation. Redpolls were introduced to New Zealand from Britain between 1862 and 1875 and are now fairly common. These birds are now usually split from the Common Redpoll (A. flammea) under the name Lesser Redpoll (Clement/eBird, HBW). However the two species are lumped under A. flammea by IOC & H&M4. Some authors place the redpolls in the genus Carduelis.
The New Zealand checklist continues to call these birds Common Redpoll although their reasons are somewhat murky. New Zealand redpolls show extensive variation and there is speculation that A. flammea which occurs in Britain as a winter visitor could have been included in shipments to New Zealand. However Fennell et el. (1985) argued that the variation seen in New Zealand redpolls could better be explained by founder effects.
The question of whether Lesser Redpoll is a valid species remains open. A recent genetic study (Mason & Taylor, 2015) found that all redpolls were similar in genetics. They found redpoll phenotypic variation is a result of RNA expressing plumage differences without differences in DNA. They advocate lumping all the redpolls into a single species. The AOU check-list committee reportedly voted to adopt their suggestion but the change was not published in the latest supplement. Canon PowerShot SX50 HS.
References:
Angus, D.J. 2013. Redpoll. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz
Clement, P. (2017). Lesser Redpoll (Carduelis cabaret). 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/61362 on 15 February 2017).
Fennell, J.F.M., Sagar, P.M. & Fennell, J.S. (1985) Variation within the Redpolls of Canterbury. Notornis 32:245-253.
Mason, N. A. and Taylor, S. A. (2015), Differentially expressed genes match bill morphology and plumage despite largely undifferentiated genomes in a Holarctic songbird. Mol Ecol, 24: 3009–3025. doi:10.1111/mec.13140