Males and females are identical in appearance. The only way to sex them is by behavior. The males will sing a song typical of many mannikins. With an upstretched neck and fluffed feathers, he will sing his warbling song and bounce back and forth on the perch while approaching the hen. (see a male in his courtship dance – click to view) They will sing often. In fact, most of the males in a cage will begin singing anytime a new member is added to the cage. There are differences in the male and female contact calls, but these are difficult to describe and you’ll have to hear them to pick them out. Males will often use this contact call while moving rapidly with quick tail flicks. There are instances of hens that will sing, but these are rare.It used to be believed that the Society finch was a fertile hybrid developed from unknown members of the Lonchura family. Tests have shown that the Society finch is a domesticated form of the White-rump mannikin. Just one look at the Chocolate self and a White-rump mannikin and there can be no doubt of their relationship.