I have 2 green cheecks, trix and rhythm. They live at the very clinic I work at. And until now have been happy to be held by anyone. This weekend me and my husband were at the clinic and I introduced him to the birds. Yesterday everything was fine the birds were content to sit with him, but today rhythm started bitting hard. She has gotten him twice now and has tried to bite both of us several times. They get plenty of time out of the cage especially on weekends. So I don't know what could b the cause. I don't know the sex of the birds or if that would even be a factor. Any ideas would be wonderful.