Barclay knew perfectly well what it was, and Mena had correctly assumed that he just called it a magpie to annoy her. Crows were famously associated with witches, and for good reason: they were clever, they were strong (for birds, anyway) and they could be deadly. Beak to the eye? Very efficient way of distracting an assailant.
Besides, crows had style. They came in murders? How cool was that?
"Yeah, because this little guy," Barclay said, looking at the bird warily, "he's gonna be a big help against a primordial spirit. What's he gonna do, peck it to death?" He nodded at Mena. "What's he called?"