鴛鴦 ・ おしどり ・ oshidori
Mandarin duck. Since (mandarin) ducks mate for life, they are considered a symbol of eternal love. The male ducks are a little more colorful than their female counterparts. Mandarin ducks are usually shown as a couple (the male's wing feathers opened and the female's wings closed), symbolizing a harmonious relationship.
In more traditional designs, apart from the open and closed wings, the male ducks have their beaks open and the female ducks their beaks closed.
Designs with mandarin ducks are also called en-ou-mon.