Geographic variation in Otus flammeolus is discussed. Size decreases steadily from north to south (although the type of idahoensis Merriam from the north is a runty misfit). Color varies enormously with geography but also has unrepentant individual variation. The blackest, most heavily marked, least red population is frontalis Hekstra of the Great Basin and Rocky Mountains. North and west from there the subspecies idahoensis is finely marked and gray. South through Mexico fine markings also prevail and red increasingly dominates the plumage of these flame-owlets of the subspecies flammeolus Kaup. Superfluous names are borealis Hekstra and rarus Griscom, both synonyms of idahoensis; and meridionalis Hekstra, a synonym of flammeolus.