The Chaco owl (''Strix chacoensis'') is an owl found in
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
,
Bolivia
, image_flag = Bandera de Bolivia (Estado).svg
, flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center
, flag_alt2 = 7 × 7 square p ...
, and
Paraguay
Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...
.
Taxonomy and systematics
The Chaco owl was originally described as a species, then quickly reclassified as a subspecies of
rufous-legged owl
The rufous-legged owl (''Strix rufipes'') is a medium-sized owl. It is found in Argentina and Chile.
Taxonomy and systematics
The rufous-legged owl has two subspecies, the nominate ''Strix rufipes rufipes'' and ''S. r. sanborni''. The latter ...
(''Strix rufipes''). A 1995 paper provided strong morphological and vocal evidence that the original treatment as a species in its own right was correct. Later work showed that it is probably more closely related to the
rusty-barred owl
The rusty-barred owl (''Strix hylophila'') is a medium-sized "typical owl" in subfamily Striginae. It is found in Argentina, Brazil (where it is known as the Brazilian owl), and Paraguay.HBW and BirdLife International (2020) ''Handbook of the B ...
(''S. hylophila'') than to the rufous-legged. It is monotypic.
[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 24 August 2021. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved August 24, 2021][Santander, F., R. A. Figueroa, M. Martínez, and S. Alvarado (2020). Chaco Owl (''Strix chacoensis''), 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.chaowl1.01 retrieved September 7, 2021]
Description
The Chaco owl is long. Males weigh and females . It has a round head with no ear tufts. Adults have a pale grayish white facial disk with concentric dark lines. Their upperparts are dusky brownish black with narrow white and yellowish buff barring. Their underparts are off-white with dark brown barring. The tail is dark grayish brown with narrow pale bars.
[
]
Distribution and habitat
The Chaco owl is found in southern South America, from Bolivia's Santa Cruz Department south through western Paraguay into north-central Argentina as far as Córdoba and Buenos Aires province
Buenos Aires (), officially the Buenos Aires Province (''Provincia de Buenos Aires'' ), is the largest and most populous Argentine province. It takes its name from the city of Buenos Aires, the capital of the country, which used to be part of th ...
s. Its elevational range is not well known, but in Argentina it is found between . It inhabits the Gran Chaco
The Gran Chaco or Dry Chaco is a sparsely populated, hot and semiarid lowland natural region of the Río de la Plata basin, divided among eastern Bolivia, western Paraguay, northern Argentina, and a portion of the Brazilian states of Mato Gro ...
, a biome characterized by low rainfall. The species is found there in hilly, rolling, and flat terrain with a wide variety of forest types, both dense and semi-open.[
]
Behavior
Feeding
The Chaco owl is primarily nocturnal but is vocally active at dawn and dusk. It hunts from a perch, dropping on or flying to small mammals, birds, reptiles, and invertebrates.[
]
Breeding
The Chaco owl's breeding phenology
Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonality, seasonal and interannual variations in climate, as well as environmental factor, habitat factors (such as elevation).
Examples includ ...
is poorly known but is assumed to be similar to that of other ''Strix'' owls. It probably nests in tree cavities or possibly holes in the ground. Captive females lay two to three eggs.[
]
Vocalization
The male Chaco owl's song is a "rather frog-like ''crococro craorr-craorr craorr-craorr'', with emphasis on the first ''craorr''". The female's song is similar but higher pitched.[
]
Status
The IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
originally assessed the Chaco owl as being of Least Concern but uprated it to Near Threatened in 2018. Its population size is not known but " is declining due to forest loss throughout its range."[
]
References
Additional reading
*König, Weick and Becking. 1999. "Owls: A Guide to the Owls of the World". Yale University Press
{{Taxonbar, from=Q1058472
Chaco owl
Birds of the Gran Chaco
Owls of South America
Chaco owl
Chaco owl