It means he eats mosquitoes or jejenes. It is the name of a genus of birds belonging to the family Tyrannidae. We also know them by the names of flycatchers, pyophytes, tyrannies, muscats, musketeers, or tiquitiquis.
Serpophaga : Genus of passerine birds of the family of tyrannids that inhabit the Neotropics and are popularly known as "piojitos", "tyrannuelos" , "tyrannoletes", "moscaretas" or "flytraps".