What does "riflebird" mean?

Riflebird: Any one of several species of beautiful birds of Australia and New Guinea, of the genera Ptiloris and Craspidophora, allied to the paradise birds. Note: The largest and best known species is Ptiloris paradisea of Australia. Its general color is rich velvety brown, glossed with lilac; the under parts are varied with rich olive green, and the head, throat, and two middle tail feathers are brilliant metallic green.