Apparently, during the Black Death, many physicians wore a mask in the shape of a bird's head. Hence, this bird-shaped Plague Doctor Mask by Bob Basset. It's on sale at eBay.
Relatedly, you can watch someone playing through Resident Evil 5 at Youtube (one of the main characters wears a bird-shaped plague mask). The first several videos are in HD and are a lot of fun to watch.
*Previously: Gas mask by Basset.
*Buy plague masks at eBay.