I am no expert but Tweetie looks like a girl, and my Coco is too and she bites like she means it. Girl budgies seem way more nippy. My Coco does like 4 step ups and try to take a piece of my finger then continues to step up like nothing happened its very odd.

I am trying to do what everyone is suggesting and it's not really working ..(the ignoring) soon i will take things a little more drastic I spoke to some trainers recently.