Did you read the article on this website about finger training? If he steps up onto the perch fine but attacks your finger then you're moving too fast. Try holding the perch with your index finger stretched out (but at the END of the perch) and when he is use to that, move your finger up along the perch...do this slowly until your finger runs along the perch where he steps up onto....Once he's doing this fine and not noticing your finger, you can move the perch and try with just the finger. If he's just nibbling your finger it's different. Marley still nibbles me when he's on my finger, it's not hard at all, I think he likes to clean my nails lol. But if he's biting hard in an aggressive way, I'd say he's still got some fear issues that you need to work on
