hummm tricky not got a macaw,
Parrot Musings: Parrot body language
i read this which gave me some insite to my bird lol an i have been bitten alot less, most importantly allow your bird to settle in to its new home and not rush it, if you want it to do anything, have a treat ready, if its holding onto a treat its harder for it to bite you, but mines dropped treat before, an nipped me anyway.
with it being all new etc you might want to pet it etc but the bird might just want to be left alone, till it is more confidant around you
what do you mean when you say hold the bird??
this is what i tell my son, let the bird go to him, have a treat ready and show parrot treat, offer his hand say step up and when parrot steps up onto his hand give her treat, if she walks away or turns, his to put treat away and do the same, i also told him to use same command as i do so not to confuse her.
but she has also learnt that my son will give in and walk the treat up to her, when his across the room

its funny to watch cos he gives her the come on (as in fly to shoulder) command and she tilts her head in a rather cute fashion, stares for a bit an he totters of to her with the treat, so maybe she is training him lol