This is an adult male. Sometimes called Goosander, this Eurasian race is similar to M. m. orientalis of Central Asia but has a longer bill and shorter wing. Both differ from American birds (M. m. americanus) by the feathering along the side of the bill base which forms a distinct wedge-shaped protrusion, and by the lack of a dark wing covert bar. Both features visible here. Canon PowerShot SX60.
References:
Carboneras, C. & Kirwan, G.M. (2019). Goosander (Mergus merganser). 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/52931 on 20 April 2019).
Pearce, J., M. L. Mallory, and K. Metz (2015). Common Merganser (Mergus merganser), version 2.0. In The Birds of North America (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.442