Yellow Naped Amazon behavior questions

Hello everyone! I'm relatively new to parrots, having just started working with them in a zoological setting a few years ago, but I adore them and have begun working with a yellow Naped. A little history on him: he was surrendered to our facility about a year and a half ago and was thought to be about 20 years old at the time. He's a pretty calm guy, but very fearful of new situations, people, etc. he wouldn't step up for anyone or have much interaction until I decided to try to start building his trust. We've done a lot of target training and he is very reliable with it. He will step up, but often makes a hissing sound and opens his beak before doing so. Many of my coworkers have pressed the issue and made him step up when he does this and then reward him profusely once he does. I've been trying to take steps to make it so he WANTS to step up which sometimes works, but then the next day he's running all over the top of his cage because "the hand" is there again. He has never bitten anyone aggressively but I don't want him to learn that he has to bite in order for someone to leave him alone.

I've also started crate training with him, which is difficult since he's terrified of any new objects. New toys, new perches, food items... If they're new, it's like armageddon is about to happen. Target comes in handy here but it takes a lot of patience.

So now that I've been working with him and we are having a better relationship I'm starting to see some new behaviors that I need some help interpreting. His vocabulary is very small and he says about three things repeatedly. Since these birds are generally known to be great talkers, is it possible he's just been so terrified in a new place that he doesn't say any of the things he knows? He's recently been making this very low pitched "oooooh" every time he steps off my hand after a training session, which id never heard him make before. His eyes start pinning and tail fans, which I know can mean excitement or aggression. He never shows any signs of aggression so I think it's excitement but I know it's a fine line!

He also did a "strut" dance after a training session last week. One of our trainers says we should avoid encouraging any of these excited behaviors, but it's also the first showing of any real personality for him. He seems to immediately pin his eyes and fan his tail lately when I enter the room. He's also been bowing his head for scratches this week and letting me pet his head. It SEEMS like he's really warming up to me, and if so, I want to make sure that we maintain a healthy relationship, not an obsessed or "could turn aggressive" type.

Anyone have any opinions? He's a wonderful bird and I absolutely adore him. I have been considering bringing him home at night with me to have a change of setting and some more human interaction, but again, I want to make sure I'm making the right choices that will result in a happy and well adjusted bird. I know that once you create habits, they're much more difficult to break, but I also want him to love me!

I would assume if you are working with the bird in a zoological setting that means you have some solid knowledge in how to act with animals, their behaviors ext... even if parrots aren't your specialty per se. Amazons are big, loud, excitable parrots and they'll let you know when they either love you or hate you with flashy displays. Sounds like this guy IS warming up and perhaps the other people are misinterpreting the behaviors or projecting the reaction he gives them onto the reaction he gives you. It's a subtle difference at times between "I'm so happy and excited to see you" and "I'm about to rip your finger off" with zons. It's also a fine line at times with just how excited they can get, which can quickly turn into overstimulation and biting due to being too wound up. Our zon pins and flashes out of sheer joy when my husband gets home from work, and is definitely happy at that time. He also pins and flashes when he's pissed and out for blood. You have to learn to read the subtle differences between the 2. We try to encourage calm behavior and calmer displays of happiness, such as 'nice' vocalizations and calmer movements. If I were you, I would give extra praise and rewards at the times he is calm with you and avoid over-encouragement when he's super excited. He will slowly learn calmness is what you want and expect from him instead of off the charts, in-your-face zon joy. They need to know what is and isn't acceptable in their human 'flock' and will learn things contrary to their 'natural' tendencies if given enough time and patience to gently encourage the calm, sweet bird out of them In regards to 'vocabulary' not all parrots are big talkers/vocalizers. Our bird has an extremely limited range of noises he makes, and we've had him for 6 years (he's about 16 now). I doubt very much he will ever pick up new noises or words. I believe parrots have a window of opportunity to learn to be vocalizers when they are very young, and if that is not encouraged, it is much harder, if not impossible for them to learn as mature birds. As for taking him home, I would only do that if the zoo would be wiling to let you keep him as your own, even if at some point in the future you no longer work for them. It would not be fair to build that kind of bond with him and then someday move on to a different job and be forced to leave him behind. If he will remain at the zoo forever, the focus should be on socializing him with many people and possibly other parrots instead of focusing on one relationship.