Qld If available, setting up a video camera to watch a pairs' interactions when left alone can be very informative about the state of the pair bond. Immaturity - be aware that each bird is not going to reach sexual maturity right on the breed average. Some birds are late developers. Younger birds also need more stimuli to breed. Older experienced birds will commence breeding much more readily.
Inexperience contributes to infertility.
Mistakes are made in courtship, mating and nesting. Style improves with age. Senescence- failure to breed due to advanced age is uncommon in aviaries even if it is common in aviculturalists. This may change as husbandry methods improve and the bird population ages. Fostered birds may become imprinted on the wrong species.