Southern bentbill

The southern bentbill was originally described in 1862 as Todirostrum olivaceum.{{cite journal | last=Lawrence |first=George N. | journal=Ibis | title=Descriptions of Six New Species of Birds from the Isthmus of Panama | volume=IV | number=XIII | page=12 | publisher=British Ornithologists’ Union | date= 1862 | url=https://www.biodiversitylibrary.org/page/8330568 | access-date=February 1, 2025 }} It was later moved to genus Oncostoma that Philip Sclater had created that same year.{{cite book | last = | first = | title =Check-list of North American Birds | publisher =American Ornithologists' Union |edition =7th | date =1998 | location =Washington, D.C. | pages =382 }}

The southern bentbill is monotypic. It shares genus Oncostoma with the northern bentbill (O. cinereigulare); in the early twentieth century at least one author considered them to be conspecific. The two form a superspecies.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 30 January 2025. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved January 31, 2025

The southern bentbill is about {{convert|9|cm|in|abbr=on}} long and weighs about {{convert|6|to|7|g|oz|abbr=on}}. It has a distinctive fairly thick downcurved bill. The sexes have the same plumage. Adults have a mostly olive head with a whitish area above the lores. Their back, rump, and uppertail coverts are olive. Their wings are dusky with lemon yellow edges on the flight feathers and greenish yellow tips on the coverts; the latter show as two indistinct wing bars. Their tail is dusky olive. Their throat and breast are yellowish white with olive streaks, their belly yellow, and their flanks olive-yellow with some olive streaks. They have a pale yellow to dusky iris, a gray bill, and dusky pinkish legs and feet.Clock, B. M. and D. A. Christie (2020). Southern Bentbill (Oncostoma olivaceum), 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.souben1.01 retrieved February 1, 2025{{cite book | last =vanPerlo | first =Ber | title =Birds of Mexico and Central America | publisher =Princeton University Press | series =Princeton Illustrated Checklists | date =2006 | location =New Jersey | pages =Plate 65, map 65.14 | isbn =0691120706 }}{{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 =154 |isbn =978-0-9827615-0-2 }}

The southern bentbill is found in central and eastern Panama from western Colón Province on the Caribbean side and the Canal Zone on the Pacific side. Its range continues into northern Colombia east most of the way to the Venezuelan border and south to Chocó and Cundinamarca departments. It inhabits the interior and edges of humid lowland evergreen forest, secondary woodlands, and shrubby clearings the tropical zone. In all landscapes it favors thickets and dense undergrowth. In elevation it ranges from sea level to {{convert|1300|m|ft|abbr=on}}.

The southern bentbill is a year-round resident.

The southern bentbill feeds primarily on arthropods and occasionally on small berries. It typically forages singly or in pairs and is not known to join mixed-species feeding flocks. It forages in dense vegetation, often near the ground but also up to the forest sub-canopy. It takes prey mostly by using short upward sallies from a perch to grab it from leaves; it then typically flies to a new perch.

The southern bentbill's breeding season has not been defined. It apparently spans at least February to June in Colombia, and single nests have been observed in April and August in Panama. Its nest is a flask or pear shaped ball with a side entrance made from plant fibers and lined with seed down; sometimes fibers dangle from the bottom. It is typically suspended from a thin branch; nests have been noted between about {{convert|1|and|4|m|ft|0|abbr=on}} above the ground. The clutch is two eggs and the female alone is believed to incubate.{{ cite book | last=Skutch | first=Alexander F. | author-link=Alexander Skutch | date=1960 | chapter=Northern bent-bill | title=Life Histories of Central American Birds II: Families Vireonidae, Sylviidae, Turdidae, Troglodytidae, Paridae, Corvidae, Hirundinidae and Tyrannidae | series=Pacific Coast Avifauna, Number 34 | location=Berkeley, California | publisher=Cooper Ornithological Society | chapter-url=https://sora.unm.edu/sites/default/files/journals/pca/pca_034.pdf#page=556 | pages=555–560 | ref=none }} Six nests had an average incubation period of about 19 days.Ricklefs, R. E. and Brawn, J. (2013). Nest attentiveness in several Neotropical suboscine passerine birds with long incubation periods. Journal of Ornithology. 154(1): 145-154. DOI 10.1007/s10336-012-0880-9.

{{birdsong|url=https://xeno-canto.org/species/Oncostoma-olivaceum |species=the southern bentbill}}

The southern bentbill's call is a "[g]uttural insect-like or toad-like trill, 'grrrrrrr' " that sometimes begins with a short note yielding "pt-trrrrrrrr". Another author says that a "[s]oft mechanical errreet [is] heard often".

The IUCN has assessed the southern bentbill as being of Least Concern. It has a large range; its estimated population of at least 500,000 mature individuals is believed to be decreasing. No immediate threats have been identified. It is considered fairly common in Panama and common in Colombia, and occurs in at least one Colombian national park.

{{Reflist}}

{{Taxonbar|from=Q1265003}}

southern bentbill

Category:Birds of Panama

Category:Birds of Colombia

southern bentbill

Category:Taxonomy articles created by Polbot