Hi Marcy,
You said
I recently purchased ... actually a female who was highly aggressive
I'm sorry you got an unwanted surprise! It sounds like you are going to try and stick with your bird, though, which is very nice. Although 2 years with no kind of ring is unusual, it may turn out to be a boy yet. If it does not, don't worry - females are nice too! In the long run, this does not matter for a pet. You should be able to reduce that aggression once you understand the source of it.
You said
She will try to dominate me by climbing on my shoulder and screeching in my ear she also frequently bites very hard and often draws
blood. When I come up to her cage she will bash against the bars and try to bite me.
These are separate behaviours and may be addressed separately..
Regarding climbing, it sounds to me like the bird is not showing dominance, but fear or lack of confidence in you or the situation. All flying types of birds will naturally seek the highest point (your shoulder, if not your head!) when they are feeling not confident or not safe, and as a matter of preference. This is not dominance. It is a natural instinct for self preservation. Some tamed birds will select this shoulder spot as their favourite and always seek it, like barn-sour horse, and I believe this should also be identified as preference, not dominance.
If this were my bird I would allow the wings to grow in and also provide a perch of at least 5 feet height in a reasonably open location. This would let the bird have both an escape route and a "safe place" to be while you get to know each other. While it would be tempting to let the bird remain on top the cage for this, I recommend against it. To do so would be to foster territoriality with regards to the cage, an undesirable condition you may already have. Please note, the bird will have to be taught to accept the new perch, as it may be initially frightening. Place the bird there and give it good treats, while refraining from any activity the bird doesn't like.
Screeching, I'm sorry, is something parrots will do. Again, this is natural. I can't tell from here what sort of screech it is, and so cannot divine the motivation. From the surrounding circumstance of being uncomfortable in a new environment with a new person, however, I could easily imagine the screech will lessen as the bird's confidence grows.
Birds can be taught to use alternate vocalizations, and at the very least may be distracted from whatever motivated the screech. Unless you can provide a video with sound, you may be on your own here. Because screeching is a natural expression, it may be quite difficult to curb. It should not, by any means, be eliminated, but rather redirected or replaced. For instance, my bird calls for me in a whistle I taught him, and I reply with a second kind of whistle, wherever in the house I may be. I never reply to screeching. Thus, the bird almost never screeches.
The bird who bites to draw blood is employing her second defense mechanism. (The first is flight.) Something in the situation is making the bird feel the need to protect herself or, by extension, her territory. Could you guess that I am about to tell you that this, too, is a natural behaviour? When the bird is comfortable in the situation, comfortable with the objects around her (including parts of your body), it is most likely the hard biting will stop. As you have noticed, there is a difference between hard defensive biting and investigatory nibbling or tasting, which is not hard.
My best advice for hard biting is to not allow the bite to happen in the first place. Of course, the most effective way to prevent a bite is to not do things that inspire the bird to defend herself. You should prevent the bird learning it as a habit, and if it is already so learned, you must allow it to fade away through lack of use. With careful observation, you will learn to predict the bite, what prompts it, and how to gently evade it. It can be as simple as blocking the bite with whatever is at hand (bowl, food, perch, toy) or simply moving out of range before the bird moves to bite. I have had great success with this method. I feel that birds who can exercise their first option of defense (flight) will not feel forced to resort to their second option (biting), and for this reason I advocate keeping the bird's wings intact. Clipping is a much-debated issue, with many facets, and you will have to find your own preference there.
When the bird tries to attack you through the cage bars, I feel she is attempting to protect her personal space (natural behaviour!), her cage, and keep you off it. She may want to keep you at a distance overall, again, for her protection. You can simply not put your hands on the outside of the cage, but this is probably not the best choice, since it will happen sooner or later that you get bitten. I had some success, and a lot of fun, addressing this with a variation of blocking. I set the bird up by holding some seeds in my fingers and then placing them against the cage bars. When my bird went to bite me, I stuffed some seeds in his mouth! He was very surprised. After a number of repetitions, the bird started just seeking seeds when I put my hand on the cage. Note well, when I stopped practicing this regularly, the biting behaviour returned, so I think it needs frequent reinforcement. Hand feeding is one of the best things you can do for communicating with your bird, so this is not at all a bad thing. Ellie may be able to give you more help with cage territoriality.
You said
She also can be very affectionate at times, she loves giving me kisses and nibbling on my jewellery (which can get a little annoying).
I caution you against falling into a trap of anthropomorphising the bird's behaviour. If the bird is actually preening you, I think you may take that as a sign of affection. If the bird is just investigating your skin, you should try to see it as exactly that. If you can clearly see what's happening, then you will be less likely to be frustrated and confused when the bird "kisses" you one minute and fiercely bites you the next. If it bothers you for the bird to nibble the jewelry, then remove it. I do think it is a good sign, however, if the bird can let down her guard enough to play with your jewelry while you are close. She will be relaxing and less defensive during that activity, and it is very good for her to associate those feelings with being close to you. Of note, you might want to replace your jewelry with bird safe things (plastic rings, DIY cardboard bracelets) during your interactions. Metals of unknown content may contain poisons, and your expensive "good" jewelry may be destroyed.
I hope you will take as much time to reflect on my post as I took to write it. I believe that once you understand how your problem behaviours have their root in natural instincts you will be in a better place, emotionally, to handle them. When you understand her motivations, you will be able to guide her to express them in a more human-acceptable way. You will also be able to set the stage for her to not need to express the least desirable defensive behaviours at all. There are many threads here on taming your bird, and they contain quite helpful information.
I wish you the very best with your bird.
-MissK
