 When he first described the red warbler in 1827 , naturalist William John Swainson assigned it to the genus Setophaga . Over the next half century , other naturalists moved it to Cardellina , with the red @-@ faced warbler , and to the widespread tropical warbler genus <unk> , as well as to the Old World warbler genus Sylvia and the Old World tit genus Parus . In 1873 , naturalists Philip Lutley Sclater and Osbert Salvin moved the species to the genus <unk> , where it remained for more than a century . 
