Have have had a few diff large birds and various reptiles.....
Birds: allot like people in that they see you as part of their flock (family) and because they don't have hands (and 1/2 the time we don't understand the vocalization) they use their beak to put us in check.
Regardless of if the requirement is:
>... "gimme"....
>... "Share you b@ztarb" ...
>... Or just "F-off"
I was bitten once by my Amazon but I turned around, grabbed her beak, held it tight and looked her in the eye for 15 seconds. That was six years ago and we still have an understanding. I understand I have to show respect and she understands I run the show. My wife gets a bite once a month and can never let the bird see her feet or there will be less than 10 toes...!
Reptiles: as much as I love them they are not as Psittaciformes..(from he perspective of complex emotion). Biting...?... I think its a mixture of their perception of heat and fear for their own space. We try to help too much sometimes because we see our babies...but most of the time they don't need us getting in the way.
My Green Iguana never harmed my hand because I trained her to respond to the sound of my fingernail tapping a glass dish (meant food) and I would get her running all over the place for the dinner bell. But when dinner was on I got out of the way and just enjoyed the girl for what she was...awesome!!
Python hatchlings...?... Too many tags to count!
My Champagne yearling...?....she's starting to scare me. I think she wants to eat my hand!
My snake hook - one of the best things I ever bought...!