The Mandarin duck (Aix galericulata) is native to the Palearctic East and closely related to the Wood Duck, Aix sponsa, the only other generic member.  Once widespread in east Asia, its has declined to about 1000 pairs each in Russia and China due to deforestation.  Japan may have about 5000 pairs, and there established feal population in other parts of the globe.  Most of the shots here are of one in Orland Park in the winter of 2019.  Probably an escapee,  and of concern to Listers, but not to photographers.  It found companionship with a female Mallard.  Being perhaps the most beautiful duck in the world, certainly the most ostentatious, results in poaching hunters being a threat also.  Because, unlike in other ducks, mates are thought to be lifelong, they are in Oriental cultures of Japan, China and Korea regarded as symbols of fidelity and wedded bliss.