Can a cockateil and ringneck mate?

by Kate
(Cape Town, South Africa)

I have a female cockateil of nearly 3 and a male indian ring neck of the same age...they have grown up together living in the same cage until about a year ago. The ring neck got a little agressive with the cockateil and i have separated them but they hang out together when they are out their cages.
Recently i have noticed that the ring neck is trying to mate with the cockateil. They both do mating dances of sorts and are no longer agressive towards each other...as i mentioned, quite the opposite.
Could they successfully mate?