There are plenty of birds out there with caps and hoods and helmets, but precious few wear a simple straightforward hat.
Brazil’s white-vented violetear is one. Today it is classified once again in the humdrum genus Colibri, but for a while in the nineteenth century, it enjoyed the pleasing and mellifluous genus name Petasophora, the “hat wearer.”
Honestly, though: If you’d had that bird lying on your desk, would the crown have been the plumage character you’d have chosen to commemorate in the name?