A Nanday Conure is an intelligent bird that can develop behavioral problems if not properly trained. It's easy to unintentionally encourage bad habits in these members of the parrot family, and keeping track of your own behavior is just as important as rewarding or disciplining the conure's behavior. In the case of an older bird that has suddenly developed bad habits, the first step is to take a look at your own behavior.
It isn't unusual for individuals to unintentionally encourage bad behavior in their Nanday Conure. Screaming can be an extremely obnoxious and frustrating, and scolding the parrot, acknowledging the behavior, or letting the bird out of its cage to quiet it may simply be making the problem worse. Doing this teaches the bird that screaming not only gets it attention, but gets it what it wants. In order to end this behavior, the bird must learn that temper tantrums are not the way to get what it wants. Ignore the conure until it is quiet, and then reward it with attention for this proper behavior.
Biting is another habit that Nanday Conures can be known for, and the basis of training the Nanday Conure not to bite is establishing yourself as the alpha or leader. The bird should never be held above chest height to reinforce that the human, not the bird, is in charge. Similarly, perches in the bird's cage should be positioned so they keep the bird in a lower, submissive position to the people in the household. Biting can be a way to challenge the alpha, and should not be tolerated, although the conure should not be hurt. An easy to way get the bird to release its bite is to shake the hand or perch that it is sitting on, forcing it to scramble to get its balance back.
A Nanday Conure that persists in showing unwanted behavior may have another reason for these bad habits. Make sure that it is not bored, and acting out because it is frustrated with a small cage, lack of toys, or loneliness. Removing any of these underlying causes can help make training much easier, and result in not only a happier bird but a stronger bond between human and parrot.
Successful training hinges on becoming the flock leader. Once the Nanday Conure accepts the fact that its human is not only the primary caretaker but also the boss, it will realize that there are boundaries it must abide by. Training creates a trusting bond between bird and owner, helps shy or timid birds gain confidence and become comfortable in their environment, and calms aggressive birds.