White-bellied antbird

The white-bellied antbird (Myrmeciza longipes), is a passerine bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds". It is found in Panama, on Trinidad, and across northern South America.<ref name=IOC14.1>Template:Cite web</ref> It is also called Swainson's antcatcher (usually in historical sources) after William Swainson, who first described it scientifically.Template:Citation needed

Taxonomy and systematics

The white-bellied antbird was described by the English naturalist William Swainson in 1825 and given the binomial name Drymophila longipes.<ref>Template:Cite journal</ref> It was moved to genus Myrmeciza in 1841 by the English zoologist George Robert Gray with it as the type species.<ref>Template:Cite book</ref> The genus formerly included more than 20 species. A molecular phylogenetic study published in 2013 found that Myrmeciza, as then defined, was polyphyletic. In the resulting rearrangement to create monophyletic genera, most of the species then in Myrmeciza were moved to 12 other genera leaving the white-bellied antbird as only the only member of the genus.<ref>Template:Cite journal</ref><ref name=IOC14.1/>

The name Myrmeciza derives from the Greek "myrmeco-" (ant) and "-izo" (ambush). The specific epithet also comes from Greek, "longi-" (long) and "-pes" (foot). Both are somewhat inaccurate, as the species is not an obligate army ant follower, does not specialize in eating ants, and does not have unusually long legs.<ref name=WBAB-BOW>DiGiovanni, A., H. S. Pollock, K. Zimmer, and M.L. Isler (2020). White-bellied Antbird (Myrmeciza longipes), 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.whbant1.01 retrieved August 12, 2024</ref>

The white-bellied antbird has these four subspecies:<ref name=IOC14.1/>

• M. l. panamensis Ridgway, 1908
• M. l. longipes (Swainson, 1825)
• M. l. boucardi von Berlepsch, 1888
• M. l. griseipectus von Berlepsch & Hartert, 1902

Some authors have suggested that some of the subspecies warrant treatment as full species.<ref>Zimmer, K.J., and M.L. Isler. 2003. Family Thamnophilidae (typical antbirds). Pp. 448-681 in "Handbook of the Birds of the World, Vol. 8. Broadbills to Tapaculos." (J. del Hoyo, A. Elliot, and D.A. Christie, eds.). Lynx Edicions, Barcelona.</ref>

Description

The white-bellied antbird is about Template:Convert long and weighs an average of about Template:Convert. Adult males of the nominate subspecies M. l. longipes have a cinnamon rufous crown, upperparts, wings, and tail. They have a hidden white patch between their scapulars. Their lesser wing coverts have white or pale buff edges and sometimes cinnamon tips. The sides of their head, their throat, and their upper breast are black and bordered with slate gray. Their lower breast and belly are white, their flanks tawny or buffy, and their undertail coverts tawny. Adult females have similar upperparts to males with the addition of black bars near the end of their wing coverts. The sides of their head are dark brown. Their chin is white, their throat and upper breast ochraceous buff, their lower breast and belly white, their flanks ochraceous buff, and their undertail coverts tawny ochraceous. Both sexes' legs and feet are pinkish gray.<ref name=WBAB-BOW/><ref name=Hilty>Template:Cite book</ref><ref name=McMullan>Template:Cite book</ref>

Males of subspecies M. l. panamensis have more black and less white on their underparts than the nominate. M. l. boucardi males have a gray crown; females are richer ochraceous on their throat and breast than the nominate. M. l. griseipectus males have black extending only slightly onto their breast and also large black spots on their wing coverts. Females have more white on their belly than the nominate.<ref name=WBAB-BOW/><ref name=Hilty/><ref name=McMullan/><ref name=vanPerlo>Template:Cite book</ref><ref name=vanPerlo2>Template:Cite book</ref>Template:Overcite

Distribution and habitat

The white-bellied antbird has a disjunct distribution. The subspecies are found thus:<ref name=WBAB-BOW/><ref name=Hilty/><ref name=McMullan/><ref name=vanPerlo/><ref name=vanPerlo2/><ref name=AOU1998>Template:Cite book</ref>Template:Overcite

• M. l. panamensis: Caribbean slope of Panama from Colón Province east, Pacific slope of Panama from Coclé Province east, and northern Colombia from extreme northern Chocó Department east to La Guajira Department
• M. l. longipes: from east slope of northeastern Colombia's Eastern Andes east through northern Venezuela to Sucre state; Trinidad
• M. l. boucardi: upper Magdalena River Valley in central Colombia
• M. l. griseipectus : east of the Andes in central Colombia's Meta Department, southern and eastern Venezuela, Guyana, Suriname, and northeastern Brazil north of the Amazon from Roraima east

The white-bellied antbird primarily inhabits the floor and understorey of moderately humid semi-deciduous forest. It also occurs in deciduous forest, small tracts of more humid rainforest, gallery forest, and shrubby secondary forest. In elevation it reaches Template:Convert in Panama, Template:Convert in Colombia, Template:Convert in Venezuela, and Template:Convert in Brazil.<ref name=WBAB-BOW/><ref name=Hilty/><ref name=McMullan/><ref name=vanPerlo/><ref name=vanPerlo2/><ref name=AOU1998/>Template:Overcite

Behavior

Movement

The white-bellied antbird is a year-round resident throughout its range.<ref name=AOU1998/>

Feeding

The white-bellied antbird feeds on a variety of insects and probably also spiders. Individuals, pairs, and family groups forage in dense vegetation mostly on the ground and also up to about Template:Convert above it. It captures prey by tossing aside and picking from leaf litter, by reaching to glean vegetation, or by jumping up to the underside of overhanging vegetation. It regularly follows army ant swarms but is not dependent on them. It seldom joins mixed-species feeding flocks.<ref name=WBAB-BOW/><ref name=Hilty/><ref name=McMullan/>

Breeding

The white-bellied antbird's breeding season has not been fully defined and appears to vary geographically, but it overall spans at least March to June. It builds a cup nest of twigs and rootlets lined with finer fibers. Its clutch size appears to be two eggs; they are white to creamy white with brown, lilac, or purple markings.<ref name=WBAB-BOW/>

Vocalization

The male white-bellied antbird's song is "a bright, ringing crescendo of 15-25 loud, rapid jeer notes...descending, trailing off, and ending in a few chew notes on [the] same pitch".<ref name=Hilty/> Females sing a similar though shorter song.<ref name=WBAB-BOW/> The species' calls include "a short, liquid rattle" and a "long...thin, downslurred whistle, sometimes abbreviated".<ref name=WBAB-BOW/>

Status

The IUCN has assessed the white-bellied antbird as being of Least Concern. It has a large range and an estimated population of at least 500,000 mature individuals. Its population is believed to be decreasing. No immediate threats have been identified.<ref name=IUCN/> It is considered fairly common to common across its range, which includes "numerous parks and reserves in nearly every country".<ref name=WBAB-BOW/>