Ancient Roman Signet Ring

First of all, I am looking for an appraisal for my own personal information. I love old Roman jewelry and I am not going to sell this ring or the others that I have. I am a seeker of knowledge and would absolutely love to know what information there is to be had about this ring.

What I know about it is that the person I bought it from says it is a zoomorphic signet ring from between the 1st and 3rd centuries. It is a size 7.5 and is made of bronze. It has an extremely nice, rather thick, dark green patina.

The symbol looks like a bird to me, but I may not be correct in this thought.

Fair