I love how this character looks very avian but also like a real person. Considering our human brains are hard-wired to read stuff on other human faces, this is a pretty impressive feat on a non-humanoid face. I've always liked your avian/gryphon character portraits. Also: purple. Those eyes are just gorgeous.
Besides i just love this artwork, forgive me to ask but: who's Sylba exactly? One thing is for sure: I want do try a griffon Miniature in the next time. And this artwork is a great guidleline for the head. The ears are a interesting idea for a Griffin. Newer saw those on another Bird till now. And they looking good.
Sylba is simply a gryphon I created She doesn't have much backstory aside from being a seer. And ears are actually quite common for gryphons! Generally they either have feathery eartufts (like an owl) or feline ears.