Hello,
I have learned through observation that birds learn from each other pretty quickly. It is amazing the intelligence these birds have and their capacity to learn and become well trained.
I have placed canaries along with zebs to teach them that eating romaine lettuce, apples, and many other fruits are okay for their enjoyment. they are now eating broccoli as well, which only one of my birds consumed. Now they all take interest soon as one bird steps forward and consumes what I have to offer.