Development stages in parrots great article, except below.
" That part of the weaning stage is particularly stressful for the young parrot. It is a gradual transition from a totally dependent state to an independent one. The young parrot will have much to learn. It is also the time of the acquisition of many social skills; the moment when the young parrot makes its "debuts" among its parrots fellows.
It must learn how to recognize the cries (dialects) of its social group (in captivity, it will learn how to associate some sounds of the human language), detect and avoid predators, find a safe place to sleep; all of the skills needed to ensure its survival and the security of its group. It is through the observation and imitation of parents and peers, that the young parrot will acquire and refine its survival skills and its social competencies.
Socialization is the process by which the bird acquires its social experience and survival skills. For the baby parrot to become a balanced adult, the same level of attention must be given to its psychological development then its physical development. The young parrot needs to receive an acceptable level of socialization to be able to evolve in its environment.
With the help of its parents and the members of its group, the young parrot will gradually accumulate new experiences until it reaches the time to be able to assume its independence. It is a gradual process for the young who will go through several levels of independence before reaching maturity. One of those levels is.... the not well-understood period of puberty."
http://www.parrot-parrots.com/important-stages-life-parrot.php
The Important Stages in the Life of a Parrot