{{Short description|Species of bird}} {{Use American English|date=September 2023}}
{{Speciesbox | name = Sharp-billed canastero | image = {{CSS image crop |Image = Sharp-billed canastero (Asthenes pyrrholeuca pyrrholeuca) Laguna Nimez.jpg |bSize = 400 |cWidth = 220 |cHeight = 200 |oTop = 40 |oLeft = 90 }}
| image_caption = El Calafate, Argentina. | status = LC | status_system = IUCN3.1 | status_ref = <ref name=IUCN>{{cite iucn |author=BirdLife International |date=2017 |title=Sharp-billed Canastero ''Asthenes pyrrholeuca'' |volume=2017 |article-number=e.T22702487A110867595 |doi=10.2305/IUCN.UK.2017-1.RLTS.T22702487A110867595.en |access-date=26 September 2023}}</ref> | genus = Asthenes | species = pyrrholeuca | authority = (Vieillot, 1817) | subdivision_ranks = Subspecies | subdivision = See text | synonyms = | range_map = Asthenes pyrrholeuca map.svg }}
The '''sharp-billed canastero''' or '''lesser canastero'''<ref name=Peña>{{cite book | last =de la Peña | first =Martín R. | last2=Rumboll |first2=Maurice| title =Birds of Southern South America and Antarctica | publisher =Princeton University Press | series =Princeton Illustrated Checklists | date =2001 | location =New Jersey | pages =Plate 63 | isbn =0-691-09035-1 }}</ref> ('''''Asthenes pyrrholeuca''''') is a species of bird in the Furnariinae subfamily of the ovenbird family Furnariidae.<ref name=IOC13.2>{{cite web |url=https://www.worldbirdnames.org/new/bow/ovenbirds/ |title=Ovenbirds, woodcreepers |website=IOC World Bird List |version =v 13.2 | editor1-last=Gill | editor1-first=Frank | editor1-link=Frank Gill (ornithologist) | editor2-last=Donsker | editor2-first=David | editor3-last=Rasmussen | editor3-first=Pamela | editor3-link=Pamela Rasmussen |date=July 2023 |access-date=July 31, 2023 }}</ref> It is found in Argentina, Bolivia, Chile, Paraguay, and Uruguay, and has also occurred as a vagrant in Brazil.<ref name=SACCcountries>Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, G. Del-Rio, A. Jaramillo, D. F. Lane, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 31 May 2023. Species Lists of Birds for South American Countries and Territories. https://www.museum.lsu.edu/~Remsen/SACCCountryLists.htm retrieved May 31, 2023</ref>
==Taxonomy and systematics==
The sharp-billed canastero's taxonomy is unsettled. The International Ornithological Committee (IOC) and BirdLife International's ''Handbook of the Birds of the World'' (HBW) assign it two subspecies, the nominate ''A. p. pyrrholeuca'' (Vieillot, 1817) and ''A. p. sordida'' (Lesson, 1839). The Clements taxonomy adds two more, ''A. p. affinis'' (Berlepsch, 1906) and ''A. p. flavogularis'' (Gould, 1839). The IOC and HBW consider ''affinis'' to be a seasonal morph of ''sordida'' and ''flavogularis'' to be a seasonal morph of the nominate ''pyrrholeuca''.<ref name=IOC13.2/><ref name=HBW7>HBW and BirdLife International (2022) Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 7. Available at: https://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v7_Dec22.zip retrieved December 13, 2022</ref><ref name=Clements2022>Clements, J. F., T. S. Schulenberg, M. J. Iliff, T. A. Fredericks, J. A. Gerbracht, D. Lepage, S. M. Billerman, B. L. Sullivan, and C. L. Wood. 2022. The eBird/Clements checklist of birds of the world: v2022. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/ retrieved November 10, 2022</ref>
This article follows the two-subspecies model.
==Description==
The sharp-billed canastero is {{convert|14|to|15|cm|in|sigfig=2|abbr=on}} long and weighs {{convert|12|to|14|g|oz|abbr=on}}. It is one of the smaller canasteros, with a pointed bill that is thinner than those of most others. The sexes have the same plumage. Adults of the nominate subspecies have a gray-brown face with a paler supercilium. Their crown is dull brown, their back and rump a slightly paler brown, and their uppertail coverts long and browner. Their wings are mostly dull rufescent brown. Their central pair of tail feathers are pointed; they and the next two pairs are dark fuscous brown with dusky tips and the rest mostly dull rufous with dark inner webs. Their chin and upper throat are rufous to tawny with dark-tipped pale streaks. Their lower throat and breast are pale grayish brown with faint streaks on the latter, their belly pale buff-brown, and their flanks and undertail coverts darker buff-brown with a rufescent tinge. Their iris is brown, their maxilla slate-gray to black, their mandible gray-horn, and their legs and feet slate-gray. Juveniles do not have the throat patch and their breast is mottled. Subspecies ''A. p. sordida'' differs from the nominate only by having entirely rufous outer tail feathers.<ref name=SBCA-BOW>Remsen, Jr., J. V. (2020). Sharp-billed Canastero (''Asthenes pyrrholeuca''), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.shbcan2.01 retrieved September 26, 2023</ref><ref name=Peña/>
==Distribution and habitat==
The nominate subspecies of the sharp-billed canastero breeds in central and southern Argentina and winters to northern Argentina and southern Paraguay and Uruguay. Subspecies ''A. p. sordida'' breeds in central and southern Chile and west-central Argentina and winters to northern Argentina and southern Bolivia.<ref name=IOC13.2/> The species inhabits a variety of semi-arid to arid landscapes including shrub-steppe, lowland and montane scrublands, and temperate, hilly, and rocky grasslands. In the non-breeding season it also occurs in tall grass, marshy areas, and Gran Chaco scrub. In elevation it mostly ranges from sea level to {{convert|2000|m|ft|abbr=on}} but locally occurs as high as {{convert|3000|m|ft|abbr=on}}.<ref name=SBCA-BOW/><ref name=Peña/>
==Behavior== ===Movement===
The sharp-billed canastero is a partial migrant. Some portion of the population moves from the south to beyond the northern limit of the species' breeding range for the austral winter.<ref name=SBCA-BOW/>
===Feeding===
The sharp-billed canastero feeds on arthropods. It usually forages singly or in pairs, gleaning prey from foliage and only rarely on the ground.<ref name=SBCA-BOW/>
===Breeding===
The sharp-billed canastero breeds in the austral spring and summer, roughly September to February. Some pairs are thought to raise two broods in a season. It is thought to be monogamous. It weaves a globular nest of small twigs up to about {{convert|30|cm|in|abbr=on}} across, with an entrance on the side or near the top. It lines the interior with hair, feathers, and soft plant material. It usually places it in the crotch of branches of a bush up to {{convert|4|m|ft|abbr=on}} above the ground. The clutch size is two to four eggs. The incubation period, time to fledging, and details of parental care are not known.<ref name=SBCA-BOW/>
{{birdsong|url=https://xeno-canto.org/species/Asthenes-pyrrholeuca |species=sharp-billed canastero}}
===Vocalization===
The sharp-billed canastero's song is "a 2-note trill, 'tsee-ee-ee-ee, tsee-ee-ee-ee' " and its contact call "a rising 'sweep' ".<ref name=SBCA-BOW/>
==Status==
The IUCN has assessed the sharp-billed canastero as being of Least Concern. It has a very large range and an unknown population size that is believed to be decreasing. No immediate threats have been identified.<ref name=IUCN/> It is considered fairly common to abundant in most of its range. Its habitat is "subjected to at least moderate grazing pressure".<ref name=SBCA-BOW/>
==References== {{Reflist}}
==External links== *[http://vireo.acnatsci.org/search.html?Form=Search&SEARCHBY=Scientific&KEYWORDS=asthenes+pyrrholeuca&showwhat=images&AGE=All&SEX=All&ACT=All&Search=Search&VIEW=All&ORIENTATION=All&RESULTS=24 Photo gallery] - VIREO
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Category:Asthenes Category:Birds of Argentina Category:Birds of Uruguay Category:Birds of Paraguay Category:Birds of Bolivia Category:Birds of Chile Category:Birds described in 1817 Category:Taxonomy articles created by Polbot Category:Taxa named by Louis Pierre Vieillot