Often called Japanese Pygmy Woodpecker, this is the most common woodpecker throughout Japan. Males have concealed dark red spots on the side of the nape visible only when the feathers are ruffled or raised. From four to eleven subspecies recognized. Here I follow IOC, H&M4 and HBW in assigning this bird from Central Honshu to the race Y. k. nippon. However, some authors merge this race with Y. k. seebohmi or Y.k. ijimae. Variation is largely clinal with northern birds being larger and paler while southern birds are smaller and darker with less white on the back, and more heavily streaked underparts. Previously included in genus Dendrocopos or Picoides but now moved to Yungipicus based on a recommendation by Fuchs and Pons (2015). Canon PowerShot SX60.
References:
Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2018. The eBird/Clements checklist of birds of the world: v2018. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
Dickinson, E.C. & Remsen, J.V. eds. (2013) The Howard and Moore Complete Checklist of the Birds of the World. 4th edition. Vol. 1. Non-passerines. Aves Press, Eastbourne, UK.
Fuchs, J. & Pons, J.M. (2015) A new classification of the Pied Woodpeckers assemblage (Dendropicini, Picidae) based on a comprehensive multi-locus phylogeny. Mol Phylogenet Evol. 88:28-37.
Gill, F & D Donsker (Eds). 2019. IOC World Bird List (v9.1). doi : 10.14344/IOC.ML.9.1. Available at http://www.worldbirdnames.org/
Winkler, H. & Christie, D.A. (2019). Japanese Pygmy Woodpecker (Picoides kizuki). 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/56213 on 14 April 2019).
Winkler, H., Christie, D.A. & Nurney, D. (1995). Woodpeckers: An Identification Guide to the Woodpeckers of the World. Houghton Mifflin