View source for Curve-billed scythebill

{{short description|Species of bird}}
{{Use American English|date=August 2023}}
{{Speciesbox
| name = Curve-billed scythebill
| image = Campylorhamphus procurvoides - Curve-billed Scythebill; Botanic Garden Tower, Manaus, Amazonas, Brazil.jpg
| image_caption = At [[Manaus]], [[Amazonas (Brazilian state)|Amazonas]], [[Brazil]]
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name=IUCN>{{cite iucn |author=BirdLife International |date=2016 |title=Curve-billed Scythebill ''Campylorhamphus procurvoides'' |volume=2016 |page=e.T103670311A93908564 |doi=10.2305/IUCN.UK.2016-3.RLTS.T103670311A93908564.en |access-date=13 August 2023}}</ref>
| genus = Campylorhamphus
| species = procurvoides
| authority = ([[Frédéric de Lafresnaye|Lafresnaye]], 1850)
| range_map =
}}
The '''curve-billed scythebill''' ('''''Campylorhamphus procurvoides''''')  is a species of [[bird]] in the subfamily [[Dendrocolaptinae]] of the ovenbird [[family (biology)|family]] [[Furnariidae]]. It is found in Brazil, Colombia, Ecuador, French Guyana, Guiana, Peru, Suriname, and Venezuela.<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>
==Taxonomy and systematics==
Taxonomists have not reached agreement on the curve-billed scythebill. The [[International Ornithological Committee]] (IOC), [[BirdLife International]]'s ''[[Handbook of the Birds of the World]]'' (HBW), and the [[Clements taxonomy]] assign it these three subspecies:<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=Clements2023>Clements, J. F., P.C. Rasmussen, T. S. Schulenberg, M. J. Iliff, T. A. Fredericks, J. A. Gerbracht, D. Lepage, A. Spencer, S. M. Billerman, B. L. Sullivan, and C. L. Wood. 2023. The eBird/Clements checklist of birds of the world: v2023. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/ retrieved October 28, 2023</ref>
*''C. p. sanus'' <small>[[John T. Zimmer|Zimmer, JT]], 1934</small>
*''C. p. gyldenstolpei'' <small>Aleixo et al., 2013</small>
*''C. p. procurvoides'' <small>([[Frédéric de Lafresnaye|Lafresnaye]], 1850)</small>
The South American Classification Committee of the [[American Ornithological Society]] adds three others, ''C. p. probatus'', ''C. p. cardosoi'', and ''C. p. multostriatus''.<ref name=SACClist>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 28 September 2023. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved October 20, 2023</ref> Until 2023 the IOC and Clements also included them. In July the IOC split off ''probatus'' and ''carsosoi'' to create the [[Tapajos scythebill]] and ''multostriatus'' to create the [[Xingu scythebill]].<ref name=IOC13.2/> Clements followed suit in October 2023.<ref name=Clements2023/> HBW had previously made those splits.<ref name=HBW7/>
Subspecies ''C. p. gyldenstolpei'' was originally proposed as a full species.<ref name=Aleixo>{{Cite book| publisher = Lynx Ediciones| isbn = 978-84-96553-88-0| volume = Special Volume: New Species and Global Index| pages = 253–257|editor= Josep del Hoyo |editor2=Andrew Elliot |editor3=Jordi Sargatal |editor4=David Christie| last1 = Aleixo| first1 = Alexandre| last2 = Portes| first2 = Carlos Eduardo B.| last3 = Whittaker| first3 = Andrew| last4 = Weckstein| first4 = Jason D.| last5 = Gonzaga| first5 = Luiz Pedreira| last6 = Zimmer| first6 = Kevin J.| last7 = Ribas| first7 = Camila C.| last8 = Bates| first8 = John M.| title = Handbook of the Birds of the World| chapter = Molecular systematics and taxonomic revision of the Curve-billed Scythebill complex (''Campylorhamphus procurvoides'': Dendrocolaptidae), with description of a new species from western Amazonian Brazil| location = Barcelona, Spain| date = 2013}}</ref>
This article follows the three-subspecies model.
==Description==
The curve-billed scythebill is {{convert|22.5|to|25|cm|in|sigfig=2|abbr=on}} long and weighs {{convert|30|to|38|g|oz|sigfig=2|abbr=on}}. It is a slim, medium-sized woodcreeper with a very long, slim, dramatically decurved bill. The sexes have the same plumage. Adults of the [[nominate subspecies]] ''C. p. procurvoides'' have a dark brown head and neck with thin whitish to buffy streaks on them and the face. Their back and wing [[Covert feather|coverts]] are olive-brown to reddish brown. Their flight feathers, rump, and tail ares rufous-chestnut that contrasts with the back. Their throat is buffy-white with a fine scaly appearance. Their underparts are dull brown with buffy-white arrow-shaped marks that become narrow streaks on the belly but don't continue onto the undertail coverts. Their underwing coverts are cinnamon-rufous. Their iris is dark brown to chestnut, their bill dark red to reddish brown (often with a dusky brown base and a paler [[mandible]]), and their legs and feet dusky green, brown, or dark gray.<ref name=CBSC-BOW>Marantz, C. A., J. del Hoyo, N. Collar, A. Aleixo, L. R. Bevier, G. M. Kirwan, and M. A. Patten (2020). Curve-billed Scythebill (''Campylorhamphus procurvoides''), version 1.0. In Birds of the World (S. M. Billerman, B. K. Keeney, P. G. Rodewald, and T. S. Schulenberg, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.cubscy1.01 retrieved August 14, 2023</ref>
Subspecies ''C. p. gyldenstolpei'' is very similar to the nominate. ''C. p. sanus'' is smaller than the nominate. It is more warmly colored with a whiter throat that is streaked instead of scaly. Its bill is shorter and more strongly decurved.<ref name=CBSC-BOW/>
==Distribution and habitat==
The subspecies of the curve-billed scythebill are found thus:<ref name=IOC13.2/><ref name=CBSC-BOW/>
*''C. p. sanus'', the [[Amazon Basin]] from southeastern Colombia, northeastern Ecuador, and extreme northeastern Peru east through southern and eastern Venezuela, extreme northwestern Brazil to the [[Rio Negro (Amazon)|Negro River]], and Guyana
*''C. p. gyldenstolpei'', southwestern Brazil south of the Amazon and west of the [[Madeira River]]; probably also in adjacent Peru
*''C. p. procurvoides'', the northeastern Amazon Basin in Brazil north of the Amazon between the Negro River and [[Amapá]] state, Suriname, and French Guiana<ref name=CBSC-BOW/> The IOC and Clements also place it in eastern Venezuela and Guyana<ref name=IOC13.2/><ref name=Clements2023/>
The curve-billed scythebill inhabits humid [[evergreen forest]]. It greatly favors ''[[Forest#Tropical moist|terra firme]]'' but occasionally occurs in floodplain forest. In southern Amazonia it often occurs in bamboo thickets. Subspecies ''C. p. gyldenstolpei'' tends to be in forest on sandy soils. In all forest types the species favors the interior though it does visit the forest edges. In elevation it mostly occurs below {{convert|500|m|ft|abbr=on}} but reaches {{convert|700|m|ft|abbr=on}} in Suriname. There is also a sight record in Venezuela at {{convert|900|m|ft|abbr=on}}.<ref name=CBSC-BOW/><ref name=vanPerlo>{{cite book | last =van Perlo | first = Ber| title =A Field Guide to the Birds of Brazil | publisher =Oxford University Press | date =2009 | location =New York | pages =206 | isbn =978-0-19-530155-7 }}</ref><ref name=Ridgely2>{{cite book | last =Ridgely | first =Robert S. | last2 =Greenfield | first2 =Paul J. | title =The Birds of Ecuador: Field Guide | publisher =Cornell University Press | volume = II| date =2001 | location =Ithaca | pages =389 | isbn =978-0-8014-8721-7 }}</ref><ref name=McMullan>{{cite book | last1 =McMullan | first1 =Miles | last2 =Donegan | first2 =Thomas M. | last3 =Quevedo | first3 =Alonso |  title = Field Guide to the Birds of Colombia | publisher = Fundación ProAves| date =2010 | location =Bogotá | pages =127  |isbn =978-0-9827615-0-2 }}</ref>
==Behavior==
===Movement===
The curve-billed scythebill is assumed to be a year-round resident throughout its range.<ref name=CBSC-BOW/>
===Feeding===
The curve-billed scythebill's diet is mostly if not entirely [[arthropod]]s. Single birds and pairs usually forage as part of [[mixed-species feeding flock]]s in the forest understory to its mid-level, though it will feed up to the subcanopy. It forages by gleaning and probing while hitching up and along trunks, branches, vines, and bamboo.<ref name=CBSC-BOW/>
===Breeding===
The curve-billed scythebill's breeding season has not been fully defined but appears to include at least February to April. It nests in cavities in trees, either natural or made by a woodpecker. The clutch size is two eggs. The incubation period, time to fledging, and details of parental care are not known.<ref name=CBSC-BOW/>
{{birdsong|url=https://xeno-canto.org/species/Campylorhamphus-procurvoides |species=curve-billed scythebill}}
===Vocalization===
The curve-billed scythebill sings mostly at dawn and only in short bursts. The subspecies' songs differ. That of the nominate is "an accelerating series...of 7–9 somewhat melancholy whistles on even pitch or falling slightly...'weeee, weé, wee, we, we, wew' or 'kuweee, kuwee, kwee, wee-wee-we-we-we. ". That of ''C. p. sanus'' "begins as series of drawn-out whistles, rapidly accelerates into fast and relatively harsh rattle, 'tweee, weee, weee, weee, weee, twe-we-we-wi-wi-i-i-i-i-wik!' ". That of ''C. p. gyldenstolpei'' has not been put into words, but "differs from that of other members in the complex in the shape and syntax of the notes, it being the only taxon to possess notes characterized by an abrupt frequency peak before their end". All subspecies give "an explosive, relatively harsh 'chit-di-dit' " call.<ref name=CBSC-BOW/>
==Status==
The [[IUCN]] has assessed the curve-billed scythebill 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 immediate threats have been identified.<ref name=IUCN/> It is considered uncommon and patchily distributed in most of its range and is rare along its western edge in Colombia, Ecuador, and Peru. It is "[h]ighly sensitive to habitat modification, requiring nearly continuous forest" and has quickly abandoned fragmented forest.<ref name=CBSC-BOW/>
==References==
{{Reflist}}
{{Taxonbar|from=Q1274841}}
[[Category:Campylorhamphus|curve-billed scythebill]]
[[Category:Birds of the Guiana Shield]]
[[Category:Birds of the Amazon rainforest]]
[[Category:Birds of the Colombian Amazon]]
[[Category:Birds of the Venezuelan Amazon]]
[[Category:Birds described in 1850|curve-billed scythebill]]
[[Category:Taxonomy articles created by Polbot]]
[[Category:Taxa named by Frédéric de Lafresnaye]]