This species is native to Africa. It was introduced to the big island starting in 1966 but has increased dramatically in recent years. In many areas it seemed to be the most common songbird. Most sources attribute this introduction to the nominate race from coastal Kenya south to northeastern South Africa). However Pyle & Pyle (2017) found that specimens more closely matched the race C. m. barbatus of Chad, Sudan and western Kenya. But barbatus is described as lacking gray on the head which does not match my photos which show fairly extensive gray as described for nominate C. m. mozambica. Females (middle image) have a less distinct head pattern. Formerly included with the siskins and goldfinches in the genus Serinus but recently moved to Crithagra to ensure generic monophyly. Canon PowerShot SX60 HS.
References
Clement, P. (2020). Yellow-fronted Canary (Crithagra mozambica). 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 https://www.hbw.com/node/61308 on 8 February 2020).
Clement, P., A. Harris, and J. Davis. (1993). Finches and Sparrows: An Identification Guide. Princeton Univ. Press, Princeton, N. J.
Pratt, H.D., Bruner, P., and Berrett, D.G. (1987) A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press.
Pyle, R.L., and P. Pyle. 2017. The Birds of the Hawaiian Islands: Occurrence, History, Distribution, and Status. B.P. Bishop Museum, Honolulu, HI, U.S.A. Version 2 (1 January 2017) http://hbs.bishopmuseum.org/birds/rlp-monograph/
Zuccon, D., Prys-Jones, R., Rasmussen, P., Ericson, P.G.P. (2012). The phylogenetic relationships and generic limits of finches (Fringillidae). Molecular Phylogenetics and Evolution. 62 (2): 581-596.