You may have read varying accounts of this striking little finch as to its level of aggression. We have one pair in our Cottage aviary because the male is aggressive towards other Cuban males but is peaceful with the other finches. This particular male who we fondly call Jack is also aggressive towards his own young once they start to colour up so we have to remove them between 3-4 weeks of age as he has killed them in the past.
However we have Jack's son Dusty in our Church aviary and Dusty is so peaceful and does not attack his own young in fact we have kept one of his son's who we call Cotchin and he is paired up now with a mate. The two Cuban pairs get along without figthing. So their are exceptions to the rule. It could be to do with space as our Church aviary is larger than our Cottage aviary or it could be a predispostion of the individual male.
They build ther own nest using fertilised small white feathers and swamp grass in the brush either in the indoor area or parts of the sheltered outdoor area. They have a small tunnel entrance into a cosy chamber. They make great parents and are extremely hardy in our Melbourne climate.
The male song is just beautiful when he calls to his partner. They are extremely loyal to each other and will cuddle up and preen each other. They are a cute little finch and a striking addition to the aviary.