Parrots can be unpredictable on a number of levels. The first, and probably one of the greatest surprises for the new parrot owner is that the bird you buy at the store or the breeder may well be nothing like the bird you will have at home.  Unless the bird has been exceptionally well socialized, it will normally remain relatively quite and subdued in the presence of strangers.  It is generally only after the bird has been in the home from several days to several weeks that it becomes comfortable enough with its new environment to let its true personality emerge.  When this happens, you might find that the bird is a biter, or a screamer.  It could be very domineering or it could be very needy.  On the other hand, it could turn out to be a sweetheart.  One never knows until the bird has settled in.  The one thing for sure is that the bird you end up with is rarely the bird you bought. 

The second common unpredictability relates to bonding.  You've got your new baby home only to find that as its personality emerges, it demonstrates a marked preference for someone else.  This can be to the total, and sometimes hostile, exclusion of you.  The bird may allow nothing from you other then to clean up it's mess without getting bitten, while gleefully playing with it's chosen one.  Birds see the members of your household as their flock.  From the flock they pick their mate and, as was mentioned in a previous section, birds pick their own mate for their own reasons.  Parrots often show a marked preference for one human gender and outright aggression toward the other.  The sex of the bird seems to have little to do with this preference, so buying a specific sex won't help.  Being the bird's primary caretaker also does not guarantee that you will be its favorite.  You should be aware in acquiring a parrot that you may end up with a bird that despises you regardless of what you do. 

If you are lucky and you stay lucky, your new parrot will bond to you and you may never experience the third unpredictability.  Generally, a parrot will bond tightly with a specific individual.  However, parrots sometime switch allegiances at the drop of a hat and for no apparent reason at all.  If someone else in your home has been the favorite until now, this might be a good thing for you.  However, if you have been the favorite and all of a sudden you are the untrusted one, this can be an emotionally painful thing.  I recently took part in a conversation with a lady who had enjoyed a very loving relationship with her Amazon for over 15 years.  Then one day, her parrot began to physically attack her every time she entered the room.  These attacks were so vicious that she had to literally spin as fast as she could to get the bird off her before suffering any more serious bite wounds to the face and neck.  On the other hand, the bird began to seek attention from her husband whom the bird had treated with total indifference before.  Why? No one really knows for sure, but it does happen. 

The last unpredictability I'll mention is frequently referred to as "going phobic".  Parrots can sometimes completely change personality for no apparent reason at all.  They show fear at the sight of anyone and retreat to the safety of their cage.  They will generally refuse to leave the cage and can become very aggressive to anyone who attempts to approach them, even the favorite person.  This behavior can go on for days, weeks, or even years unless the cause is found and corrected.  As prey animals, birds see and watch EVERYTHING in their environment until they are convinced it is not a threat.  Many changes go by with no reaction from the bird at all, and then suddenly the smallest change can trigger the phobic reaction.  That is what makes the cause so hard to find.  It could be loose change innocently laid on an adjacent table, a new decorative object or drapes.  Maybe it's your new glasses or hat.  It could be just about anything that changes. 

Studies have shown that parrots have, on average, the emotional complexity of up to a four year old human (the largest birds and some Amazons & Greys) Just like humans, they will have their up-days and their down-days ... their temper tantrums and their jumps for joy.  Some of these swings will last for minutes or hours.  Some may last much longer.  The point of this section is to make you aware that parrots change as time passes, just as humans do.  To be a successful parrot owner, you will need to be adaptable and willing to change along with the bird.  If you can't see yourself doing that for the next 20 to 80 years, then you would be well advised to seek some other kind of pet.