Family Typical Owls (Strigidae)

Least Concern

Stygian Owl (Asio stygius)


French: Hibou maître-bois German: Styxeule Spanish: Búho negruzco

Nyctalops stygius


, 1832,

Minas Gerais, Brazil


Has been proposed that species be included in Pseudoscops, but DNA studies appear to confirm its placement in Asio; closely related to A. otus. Populations of NW South America usually placed in subspecies robustus, sometimes included in nominate; races lambi, noctipetens and barberoi rather poorly differentiated, possibly not valid. Six subspecies recognized.

Subspecies and Distribution
  • A. s. lambi R. T. Moore, 1937 – W Mexican highlands (SE Sonora and SW Chihuahua S to Jalisco).
  • A. s. robustus L. Kelso, 1934 – S Mexico (Guerrero and Veracruz) S discontinuously to NW Venezuela, Colombia, Ecuador and N Peru.
  • A. s. siguapa (d’Orbigny, 1839) – Cuba and I of Pines.
  • A. s. noctipetens Riley, 1916 – Hispaniola and I de Gonâve.
  • A. s. stygius (Wagler, 1832) – N Brazil S through C Amazonia to E Bolivia, NE Argentina and SE Brazil.
  • A. s. barberoi A. W. Bertoni, 1930 – Paraguay and N Argentina (S to Santiago del Estero).
  • Descriptive notes

    38–46 cm; female 685 g, male 460 g (n = 1 of each sex), unsexed 408 g. Large, dark owl with prominent ear-tufts. Whitish forehead contrasts with blackish... read more


    Male gives a single deep, emphatic “whuoh”, repeated at intervals of 6–10 seconds... read more


    Montane pine and pine-oak forest, submontane evergreen forest, deciduous forest, humid Chaco... read more

    Food and feeding

    Small mammals such as rodents and bats; also birds, reptiles, crustaceans and insects. Thirty-four prey items from pellets collected in... read more


    Rather poorly studied. Nesting can occur in almost any month of year, the timing varying with latitude and climatic regime; chicks... read more


    Little known, probably largely resident. Suspected visitor during Feb–Apr on Cozumel I, off... read more

    Status and conservation

    Not globally threatened (Least Concern). CITES II. No estimation of global population size; BirdLife International posits that numbers are declining in some areas. Considered... read more

    Recommended citation

    Olsen, P.D., Kirwan, G.M. & Marks, J.S. (2019). Stygian Owl (Asio stygius). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 14 December 2019).