I think when one takes into consideration not just the bird's head pommel and rendering of the feathers, but also the stylings of the
rest of the hilt and the blade - in totality - it is likely to be of European Colonial origin.
I have never seen anything attributed to the Middle East that looked even remotely similar, and I would challenge the claim of use of this motif in Japanese or Chinese sculpture as well. To equate a questionable attribution to a published collection to an unqualified attribution to cultural complexes to which there is no stylistic input that would merit such a consideration is a false equivalency at best, as while this bird (head) rendering deos not resemble any of the published examples in the Medicus collection, there are plenty of obvious attributes IMO - the hangar blade, the s-curve quillons, the guard - to suggest a Colonial attribution.
Neither is
what bird is represented on the pommel a red herring IMO, as recognized stylistic similarities are helpful - if not important - in helping identify from region of influence this sword came.
To my eye, a Spanish Colonial attribution seems most likely, though 'Nando's last post does introduce the interesting possibility of Indian manufacture, as there is a 'character' about the brass casting that for whatever reason recalls Indian brasswork to me.