This is an adult male showing its red crown and bicolored bill. This species is reported to have a light eye, but eye color is apparently variable, appearing dark in this photo. Although fairly widespread, we encountered this species only in Corbett. Canon PowerShot SX50 HS.
References:
Rasmussen, P.C. & Anderton, J.C. (2012) Birds of South Asia. The Ripley Guide. Vols. 1 and 2. Second Edition. Smithsonian Institution. Michigan State University & Lynx Edicions, Washington. D.C., Michigan & Barcelona.
Winkler, H. & Christie, D.A. (2016). Streak-throated Woodpecker (Picus xanthopygaeus). 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/56310 on 3 September 2016).
Winkler, H., Christie, D.A. & Nurney, D. (1995) Woodpeckers: A guide to woodpeckers of the world. Houghton Mifflin.