Avian reproductive behaviors observed in the wild…
…such as pair bonding, courtship regurgitation, cavity seeking, nest building, territorial aggression, and copulation, are often displayed in a home setting, though with human “flocks”. Females of some species lay large numbers of eggs over extended periods of time to a point of complete physical collapse and failure.
The reproductive drive can also lead to behaviors that render the bird difficult or impossible to live with. These behaviors often include incessant screaming, sudden aggression towards favored (or not favored) humans, and destructive attempts to excavate nests in closets, couches, and drawers.
As many species are represented in the pet trade, there exists extreme variability as to when behaviors will start, which will be displayed, and how long they may continue.
Read the full article about Problem Sexual Behaviors in Companion Parrots.