Why is my bird obsessed with biting and destroying my fingernails

It's possible it's a nervous habit, but I think he probably just needs the tips cut off so he feels a bit more comfortable walking around. It wouldn't hurt to trim them and then see if he still continuously chews them just to try and gauge what it is he's trying to accomplish. Sometimes, nail biting can be a sign of emotional or mental stress. It tends to show up in people who are nervous, anxious or feeling down. It's a way to cope with these feelings. You may also find yourself doing it when you're bored, hungry or feeling insecure. Many bird species are incredibly smart. Yet among intelligent animals, the “bird brain” often doesn't get much respect. Two papers published today in Science find birds actually have a brain that is much more similar to our complex primate organ than previously thought. She/he is possibly nervous and see's you do it and is mimicking it(?)

Maybe he/she is Nervous, you May want to have him/her checked out, i hope he/she is okay! And he/she is Beautiful! ^^

c. live where it’s cold and icy