Stygian owl

The Stygian owl (Asio stygius) is a medium-sized "typical owl" in subfamily Striginae. It is found in Mexico, parts of Central America, Cuba, Hispaniola, and 10 countries in South America.[3][4][5]

Stygian owl
CITES Appendix II (CITES)[2]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Asio
Species:
A. stygius
Binomial name
Asio stygius
(Wagler, 1832)

Taxonomy and systematics

The Stygian owl has these six recognized subspecies:[3]

Description

The Stygian owl is 38 to 46 cm (15 to 18 in) long and weighs about 400 to 675 g (14 to 24 oz). The sexes have similar very dark plumage. (The adjective "Stygian" means "of, or relating to, the River Styx", but is more widely applied to anything that is dark or dismal.) The face is blackish with a pale border and a whitish forehead, and the head has long dark feathers that project upward as "ears". The dark upperparts have buff streaks and bars; the underparts are a dingy buff with dark brown or blackish barring and streaks. The eye is shades of yellow, the bill blue-black to blackish, and the feet dark grayish or brownish pink. The subspecies are substantially alike, differing mostly in the shade of the upperparts' streaks and somewhat in size.[6]

Distribution and habitat

The subspecies of Stygian owl are found thus (but see the text below the list):[3][6]

  • A. s. lambi, northwestern Mexico from Sonora and Chihuahua south to Jalisco
  • A. s. robustus, discontinuously from Guerrero and Veracruz in Mexico south into northern Nicaragua
  • A. s. siguapa, mainland Cuba and Isla de la Juventud (Isle of Pines)
  • A. s. noctipetens, mainland Hispaniola and Gonâve Island
  • A. s. stygius, Colombia and Venezuela south to Bolivia and discontinuously in central and southern Brazil
  • A. s. barberoi, Paraguay and northern Argentina

In addition, the Stygian owl has been documented as a vagrant in Texas, Florida, and Trinidad.[7][8][9][10]

Some authors merge A. s. lambi into A. s. robustus. Some extend the range of robustus to include the Colombian, Ecuadorian, and Venezuelan populations otherwise attributed to A. s. stygius. Some include A. s. noctipetens in A. s. siguapa. And some include the population in southeastern Brazil in A. s. barberoi instead of in A. s. stygius.[6]

The Stygian owl inhabits a wide variety of landscapes from sea level to 3,000 m (9,800 ft) of elevation. Most are fairly open rather than densely forested or purely grasslands. They include montane pine, pine-oak, and cloud forests, thorn scrub, cerrado, pine plantations, and even urban parks.[6]

Behavior

Movement

As far as is known, the Stygian owl is resident throughout its range.[6]

Feeding

The Stygian owl is wholly nocturnal. The largest part of its diet is birds, from very small ones to some as large as the 150 g (5.3 oz) lesser nothura (Nothura minor); it is thought that most birds are caught on their nighttime roosts. The diet also includes bats (which are seldom preyed on by other owls), some other mammals (like Hispaniolan solenodons[11]), frogs, and insects. Also, in contrast to other owls, rodents do not appear to be part of its diet.[6]

Breeding

The Stygian owl's breeding phenology is not well known. Its breeding seasons vary widely across its range. Males give a wing-clapping display in flight. It nests on the ground or in trees; in the latter it apparently reuses nests of other species. It lays two or three eggs.[6]

Vocalization

The Stygian owl's song has been variously described as "a single deep, emphatic woof or wupf", "a very low and loud hu or hu-hu", and "a muffled hoot given singly: boo". Females also give "a short, screamed rre-ehhr or mehrr" when calling to the male, and also "a short catlike miah".[6]

Status

The IUCN has assessed the Stygian owl as being of least concern. It has a very large range, but its population size is not known and is believed to be decreasing. No specific threats have been identified.[1]

References
  1. BirdLife International (2016). "Stygian Owl Asio stygius". IUCN Red List of Threatened Species. 2016: e.T22689504A95214500. doi:10.2305/IUCN.UK.2016-3.RLTS.T22689504A95214500.en. Retrieved 8 March 2022.
  2. "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. Gill, F.; Donsker, D.; Rasmussen, P., eds. (January 2022). "Owls". IOC World Bird List. v 12.1. Retrieved January 15, 2022.
  4. HBW and BirdLife International (2020) Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world Version 5. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v5_Dec20.zip [.xls zipped 1 MB] retrieved 27 May 2021
  5. Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, A. Jaramillo, D. F. Lane, J. F. Pacheco, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 31 January 2022. Species Lists of Birds for South American Countries and Territories. https://www.museum.lsu.edu/~Remsen/SACCCountryLists.htm retrieved February 1, 2022
  6. Arizmendi, M. d. C., C. I. Rodríguez-Flores, C. A. Soberanes-González, and T. S. Schulenberg (2020). Stygian Owl (Asio stygius), version 1.0. In Birds of the World (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.styowl1.01 retrieved March 8, 2022
  7. "Texas State List". Texas Bird Records Committee (TBRC) of the Texas Ornithological Society. December 9, 2021. Retrieved March 8, 2022.
  8. "Stygian Owl". Archived from the original on 2007-08-14. Retrieved March 8, 2022.
  9. "Official Florida State Bird List". Florida Ornithological Society Records Committee. 2022. Retrieved March 8, 2022.
  10. Kenefick, Martyn (September 22, 2020). "Species lists of birds for South American countries and territories: Trinidad and Tobago". South American Classification Committee of the American Ornithological Society. Retrieved March 8, 2022.
  11. Jonathan J. Derbridge et al., "Solenodon paradoxus (Soricomorpha: Solenodontidae)," Mammalian Species, Volume 47, Issue 927, 2015, Pages 100 - 106.
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