Cercomacra
| Cercomacra | |
|---|---|
| |
| Rio Branco Antbird (Cercomacra carbonaria) | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Thamnophilidae |
| Genus: | Cercomacra |
| Type species | |
| Cercomacra Brasiliana
,Cercomacra Carbonaria,Cercomacra Cinerascens,Cercomacra Ferdinandi,Cercomacra Manu,Cercomacra Melanaria,Cercomacra Nigricans | |
Cercomacra is a genus of passerine birds in the family Thamnophilidae.[1] It commonly known as an antbird. They are insect-feeding birds that mainly inhabit tropical and subtropical forest areas of South America.[2][3][4][5][6][7][8][9] Habit of some species under this genus extending into Central America.[7] Cercomacra is independent of other bird genera for its sexual dimorphism and communication ways.[1][10] They often forage and feed close to the ground or in low vegetation.[1] A molecular phylogenetic study has shown that the traditional genus Cercomacra is not monophyletic but is divided into two distinct lineages: the “nigricans” group, which retains the original genus name, and the “tyrannina” group, now recognized as the separate genus Cercomacroides.[1]
Historical Discovery and Naming Context
[edit]Cercomacra was formally described by the British zoologist Philip Lutley Sclater in his paper "Synopsis of the American Ant-Birds (Formicariidae)" submitted to the Zoological Society of London in 1858. At that time, Sclater was dedicated to classifying neotropical antbirds based on detailed morphological comparisons, focused on the tarsal scutes, tail length, and feather characteristics.[10] The antbirds included in the genus Cercomacra are relatively large, have unicolored feathers and wide, flat beaks, and have become an independent genus, distinguished from genera such as Formicivora and Pyriglena.[10] At that time, Cercomacra represented a transitional genus between Formicivora and Pyriglena, but Cercomacra retained sufficient structural features to prove that a single genus was correct. His classification was based on wild specimens from various regions of South America, including Brazil and the upper reaches of the Amazon River.[11] These specimens have been studied in the collections of museums such as the British Museum and the Paris Museum of Natural History.[11]
Sclater’s description laid the foundation for the taxonomic processing of this genus for more than a century.[12][13][14] It remained relatively stable until molecular techniques in the 21st century revealed its polylineal structure, leading to subsequent reclassification.[1]
Taxonomy and Classification
[edit]The genus was erected by the English zoologist Philip Sclater in 1858.[10] It belongs to the family called Thamnophilidae.[10] Historically, Cercomacra was regarded as a monophyletic genus comprising 12 species.[14][15] However, molecular studies conducted in 2014 revealed that the genus consists of two distinct clades.[1] The results of this reclassification study have reached a consensus within the industry.[16]
Change to Phylogenetic
[edit]A comprehensive molecular phylogenetic study based on the analysis of three mitochondrial gene regions (NADH dehydrogenase subunit 2 (ND2), NADH dehydrogenase subunit 3 (ND3), and cytochrome b (CYTB) and one nuclear intron (β-fibrinogen intron 5 (FIB5) sequencing revealed that the traditional Cercomacra genus was not a monophyletic group.[1] The finding led to a taxonomic revision: the “nigricans” clade retained the name Cercomacra, while the “tyrannina” group was elevated to a new genus, Cercomacroides.[1][12][17]
Reclassification of Genus and Establishment of New Genus
[edit]The reclassification was based on differences in genetics, morphology, vocalizations, and ecological preferences.[1]
The “nigricans” clade retain the original genus name, containing 7 species: Cercomacra Nigricans, Cercomacra Carbonaria, Cercomacra Ferdinandi, Cercomacra Melanaria, Cercomacra Manu, Cercomacra Brasiliana, and Cercomacra Cinerascens.
The “tyrannina” clade was separately established as a new genus, Cercomacroides, and includes 5 species: Cercomacroides Tyrannina, Cercomacroides Serva, Cercomacroides Nigrescens, Cercomacroides Laeta, and Cercomacroides Parkeri.
Cercomacra generally have white tail spots, olive-grey to grey-brown females, and produce complex, synchronized duet songs.[1] In contrast, Cercomacroides lacks white tail markings, features tawny-buff females, and exhibits asynchronous singing behavior.[1] Ecologically, Cercomacra tend to occupy mid-canopy forest layers, while Cercomacroides favors edge habitats and dense shrub layers in secondary forests.[1] The genus now contains seven species:[18]
| Image | Common Name | Scientific Name | Distribution |
|---|---|---|---|
.jpg) |
Manu antbird | Cercomacra manu | southern Amazonia |
 |
Rio de Janeiro antbird | Cercomacra brasiliana | Bahia forests |
 |
Grey antbird | Cercomacra cinerascens | Amazonia |
.jpg) |
Mato Grosso antbird | Cercomacra melanaria | Bolivia and Pantanal |
.jpg) |
Bananal antbird | Cercomacra ferdinandi | Araguaia River |
 |
Jet antbird | Cercomacra nigricans | Panama, Colombia, Venezuela and Ecuador |
|
Rio Branco antbird | Cercomacra carbonaria | Branco River |
Research Methodology in Reclassification
[edit]The original classification of Cercomacra was determined to be reclassified through molecular phylogenetic analysis.[1] Molecular phylogenetic analysis used mitochondrial and nuclear genetic markers to reconstruct evolutionary relationships within genera.[1] The mitochondrial genes analyzed include NADH dehydrogenase subunit 2 (ND2), subunit 3 (ND3), and cytochrome b (CYTB).[1] These genes are widely used in the study of avian phylogeny due to their high mutation rate and maternal inheritance. To further confirm that there were two types of antbird species with different evolutionary directions in the original genus Cercomacra, β -fibrinogen intron 5 (FIB5) was also used in the reclassification study. This is a slower evolving nuclear marker that provides broader evolutionary signals.[1]
The sequences were compared and analyzed using maximum likelihood and Bayesian inference methods to generate phylogenetic trees.[1] To verify the hypothesis that Cercomacra is monophyletic, the related studies used the SOWH test, which is a statistical method for comparing the topological structures of constrained and unconstrained trees.[1] The results strongly oppose the monophyletism of the traditional genus and support its division into two distinct branches. The time estimation of differentiation using the BEAST software ultimately determined that the evolutionary split of the nigricans and tyrannina groups occurred from the late Miocene to the early Pliocene (approximately 9 to 4.2 million years ago).[1] This finding let people know that there is a profound and significant separation in evolution.[1]
Morphology and Behaviour
[edit]Morphology
[edit]Species in Cercomacra are small to medium-sized antbirds, measuring approximately about 13 to 16.5 cm (5.1 to 6.5in) in length and weighing between 14 and 20 grams (0.49 to 0.71 oz).[2][3][4][5][6][7][8] They display strong sexual dimorphism in plumage.[1] Males are predominantly black or dark gray plumage with distinctive white spots or tips on their tail feathers.[2][3][4][5][6][7][8] Females display more subdued olive-grey or greyish-brown plumage. Females of Cercomacroides usually displaying tawny-buff plumage.[1]
The characteristics of Cercomacra are noticeable when displayed and flown. Cercomacra has strong legs and feet, allowing them to move around in dense vegetation. They have relatively short wings suited for fast, agile movement rather than sustained flight.[1]
Communication Behaviour
[edit]Species within the Cercomacra communicate each other through the complex vocal duets.[1][17] These coordinated songs are usually performed between paired males and females. This kind of communication behaviour playing a central role in defending territory and strengthening their partner bonds.[14]
The structure of these vocalizations usually consists of rapid, rhythmic short note exchanges with distinct arrangement between males and females.[14] This coordinated singing behavior helps maintain strong pairing bonds and facilitates reproductive isolation between close relatives who share similar habitats.[14]
In addition to vocal duets, Cercomacra also exhibits visual behaviors such as tail flicking and subtle wing movements, especially during territorial displays or close interactions.[1][14] These actions may enhance their acoustic signals transfer.[14]
Nesting and Reproduction Behaviour
[edit]Species of the genus Cercomacra typically place open cup-shaped nests horizontally in dense vine tangles or low vegetation in tropical forests.[1] Nest placement and construction provide camouflage and protection from the predators of those antbirds and inclement weather.[14] These nests are usually relatively close to the ground or in the understory of the forest. Male and female birds share nesting duties, which includes building, incubation and feeding. Those behaviours can reinforce their strong pair bond.[2][3][4][5][6][7][8][14]
Their use their specific communication ways to facilitate the reproductive behaviours, The reproductive success means that the paired birds are safe than before.[14][19] The reproductive behaviour increased their ability to survive.[1] In addition, the nesting behaviours are different from Cercomacra to Cercomacroides. The Cercomacroides always build deep pouch-like nests suspended from vegetation.
Foraging and Feeding Behaviour
[edit]The species under the genus of Cercomacra are insectivorous.[1][14][19] They usually find their foods from leaves and branches. They eat insects and other small arthropods that grow in the understory and mid-canopy of dense tropical forests.[14] While the Cercomacra occasionally prey on insects disturbed by swarms of army ants, their participation in ant-following behavior is usually opportunistic rather than obligatory.[19] Their foraging behavior usually involves short and agile movements through tangled vegetation.[19] They can achieve those movements benefits from their typical tail-flicking and wing movements. To contrasts with other ant-following antbirds, which rely heavily on ant colonies for food, the food source of Cercomacra are not predominantly by the single approach.[19]
Perching and Roosting Behaviour
[edit]Cercomacra is often hidden in dense vegetation, which in the lower to middle level strata of tropical forests.[1] During their vocal displays, individuals may move to more exposed branches to have the better transmissions.[14] Their perching behaviour is usually brief, followed by quick and agile jumps or flights to feed or patrol their territory.[19]
The roosting behavior of Cercomacra is not well observed and documented, but available observations suggest that individuals perching alone or in pairs, hidden in vine tangles or dense foliage, may reduce the risk of predation.[14] Some biologists suggested that Cercomacra may prefer thick cover during both active and resting periods.[1][14][19]
Distribution and Ecology
[edit]Geographic Range
[edit]Species within Cercomacra genus are distributed across the Neotropical region.[1] This region is mainly in the Amazon basin and adjacent lowland rainforests. Species within Cercomacra genus range from southern Central America, such as Panama, to northern and central of South America.[2][3][4][5][6][7][8] They can be found in those regions includes countries such as Colombia, Venezuela, Brazil, Peru, Bolivia, and Guyana.[2][3][4][5][6][7][8] Most species are found in the humid tropical forests of the Amazon, some, such as Cercomacra brasiliana, are limited to Brazil's Atlantic Forest.[9] However, Cercomacra manu inhabit bamboo-dominated forests in the foothills of the Andes.[12]
Species within Cercomacra genus usually occupy dense understory of forests as their habitats. They prefer to choose the near forest edges or tangled with vines for the safety and feeding considerations.[1][14]
Ecological Role
[edit]Cercomacra plays a modest important ecological role in the tropical forest ecosystem. As the species under the Cercomacra genus eat the arthropods, the populations of arthropods will be consisted into a safe level.[1][14][19] This fact contributes to the balance of forest invertebrate communities. Their active foraging in the lower and middle level strata allows them to exploit niches that are difficult for larger or more specialized insectivorous animals to access.[19]
Their nesting habits interact with plant layers. They try to using vine tangles and low vegetation as nesting sites, which can affect seedlings and understory structures.[1][19] For instance, they facilitate the seedling of the vegetation when they movements through the forest.[19]
The species within the genus of Cercomacra are also an essential part of the food chain.[20] They prey on arthropods as predators. The predators, such as snakes, also prey on them.[20]
Ecological Significance and Evolutionary Insights
[edit]There is a wide range of interactions between birds and ants, and they have ecological impacts. Of the 131 existing avian families, more than 11% interact with ants.[21] Among them, antbirds - including the genus Cercomacra - stand out particularly in tropical biomes, where they engage in complex relationships such as symbiosis, competition and predation.[21] In most studies of other genus under the antbirds, there is abundant evidence confirming that antbirds have colony following behavior.[22] However, unlike other genus, Cercomacra is usually regarded as an opportunistic participant in this interaction, which is the ant-following behaviour.[19] They benefit from the prey of the ant colony but do not often employ this strategy.[19] This interaction between ant and antbird places Cercomacra in a broader ecological chain, which helps to build a food web in tropical forests.[21]
From an evolutionary perspective, there is a strong phylogenetic signal in antbirds that tends to interact symbiotically and competitively with ants.[21] As a genus under antbirds family, Cercomacra and its close relatives can not only serve as models for vocalization and social behavior, but also are of great significance for understanding the co-evolutionary dynamics of the bird-invertebrate system.[21]
Conservation Status
[edit]IUCN Data
[edit]| Species | Image | IUCN Data | Description | |
| Cercomacra Brasiliana | Rio de Janeiro Antbird | |
NT | Near Threatened |
| Cercomacra Carbonaria | Rio Branco Antbird | ;_Ramal_do_Noca,_Rio_Branco,_Acre,_Brazil.jpg) |
VU | Vulnerable |
| Cercomacra Cinerascens | Grey Antbird | |
LC | Least Concern |
| Cercomacra Ferdinandi | Bananal Antbird | |
NT | Near Threatened |
| Cercomacra Manu | Manu Antbird | |
LC | Least Concern |
| Cercomacra Melanaria | Mato Grosso Antbird |  |
LC | Least Concern |
| Cercomacra Nigricans | Jet Antbird | |
LC | Least Concern |
The IUCN Red List of Threatened Species is the most comprehensive global inventory of the conservation status of plant and animal species. Each species is assigned to a conservation category ranging from least concern (LC) to extinct (EX), with intermediate levels such as near Threatened (NT), vulnerable (VU), Endangered (EN) and critically endangered (CR).[23]
Most species, including Cercomacra Nigricans, Cercomacra Melanaria, Cercomacra Manu, and Cercomacra Cinerascens are assigned to the consercation category of least concern (LC). The Cercomacra Brasiliana, and Cercomacra Ferdinandi are assigned to the category of Near Threatened (NT). The Cercomacra Carbonaria is assigned to the category of Vulnerable (VU). Most species are in the safe level, but all species are undergoing the decreasing trend.[23]
Threats and Protection
[edit]Most species within Cercomacra genus are not currently listed as globally endangered. However, their populations are being affected by their habitat loss and fragmentation.[24] The human footprints in tropical South America, including deforestation, agricultural expansion and infrastructure development, are the main reason to the decreasing population of Cercomacra.[24]
Species with narrow ranges or special habitat requirements, such as Cercomacra Brasiliana, face vulnerability due to the human footprints in their ecosystems.[1] Logging and deforestation have destroyed the dense understory environments that these birds rely on for food, nesting and habitat.[1][24] Several populations of Cercomacra inhabit in protected areas such as national parks and biological reserves, but the effect is weak.[24] The long-term conservation depends on the protection of large contiguous areas of forest.[24]
Observation Through Visual and Sound Archives
[edit]Like many tropical forest birds, due to their secretive behavior and dense habitats, species of the genus Cercomacra are usually difficult to observe in the wild. However, a wide variety of resources enable researchers and bird lovers to access high-quality visual and acoustic materials for identification and educational purposes. Many high quality photos of Cercomacra can be obtained through online bird photography databases, such as the Cornell Lab of Ornithology, including all the species included in the genus Cercomacra.[2][3][4][5][6][7][8]
What is particularly notable about the vocalization of the Cercomacra species is their complex duet. There are also many audio resources of Cercomacra on the website of Cornell Lab of Ornithology.
References
[edit]- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj Tello, Jose G.; Raposo, Marcos; Bates, John M.; Bravo, Gustavo A.; Cadena, Carlos Daniel; Maldonado-Coelho, Marcos (12 March 2014). "Reassessment of the systematics of the widespread Neotropical genus Cercomacra (Aves: Thamnophilidae): Polyphyly of Cercomacra". Zoological Journal of the Linnean Society. 170 (3): 546–565. doi:10.1111/zoj.12116. ISSN 1096-3642 – via Wiley Online Library.
- ^ a b c d e f g Schulenberg, Thomas S.; Rosenberg, Gary H. (2020-03-04), Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.), "Manu Antbird (Cercomacra manu)", Birds of the World, Cornell Lab of Ornithology, doi:10.2173/bow.manant1.01, retrieved 2025-05-30
- ^ a b c d e f g Zimmer, Kevin; Isler, Morton L. (2020-03-04), Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.), "Rio de Janeiro Antbird (Cercomacra brasiliana)", Birds of the World, Cornell Lab of Ornithology, doi:10.2173/bow.rdjant1.01, retrieved 2025-05-30
- ^ a b c d e f g Zimmer, Kevin; Isler, Morton L. (2020-03-04), Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.), "Gray Antbird (Cercomacra cinerascens)", Birds of the World, Cornell Lab of Ornithology, doi:10.2173/bow.gryant2.01, retrieved 2025-05-30
- ^ a b c d e f g Zimmer, Kevin; Isler, Morton L.; de Juana, Eduardo (2020-03-04), Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.), "Mato Grosso Antbird (Cercomacra melanaria)", Birds of the World, Cornell Lab of Ornithology, doi:10.2173/bow.magant1.01, retrieved 2025-05-30
- ^ a b c d e f g Zimmer, Kevin; Isler, Morton L. (2020-03-04), Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.), "Bananal Antbird (Cercomacra ferdinandi)", Birds of the World, Cornell Lab of Ornithology, doi:10.2173/bow.banant1.01, retrieved 2025-05-30
- ^ a b c d e f g h Zimmer, Kevin; Isler, Morton L. (2020-03-04), Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.), "Jet Antbird (Cercomacra nigricans)", Birds of the World, Cornell Lab of Ornithology, doi:10.2173/bow.jetant1.01, retrieved 2025-05-30
- ^ a b c d e f g Zimmer, Kevin; Isler, Morton L.; Sharpe, Chris (2020-03-04), Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.), "Rio Branco Antbird (Cercomacra carbonaria)", Birds of the World, Cornell Lab of Ornithology, doi:10.2173/bow.ribant1.01, retrieved 2025-05-30
- ^ a b Melville, Don; Ignacio, Leroy; Millar, Neal; Merritt, Vanessa; Kays, Roland; Cyril, Samuel; David, Dereck; Ignace, Abraham; Johnny, Angelbert; Johnny, Frank; Thomas, Flavian; Wilson, Asaph; Wilson, Nate; O’Shea, Brian (2024). "New surveys reveal a population stronghold for the Hoary-throated Spinetail Synallaxis kollari and Rio Branco Antbird Cercomacra carbonaria along the Guyana–Brazil border". Bird Conservation International. 34. doi:10.1017/S0959270924000170. ISSN 0959-2709.
- ^ a b c d e Sclater, Philip Lutley (1858). "Synopsis of the American Ant-birds (Formicariidae). Part II containing the Formicivorinae or Ant-wrens". Proceedings of the Zoological Society of London. Part 26: 232–254 [244].
- ^ a b Sclater, Philip Lutley (1858). "Synopsis of the American Ant-Birds (formicariidæ)". Proceedings of the Zoological Society of London. 26 (1): 202–224. doi:10.1111/j.1469-7998.1858.tb06365.x. ISSN 1469-7998.
- ^ a b c Fitzpatrick, John W.; Willard, David E. (April 1990). "Cercomacra manu, a New Species of Antbird from Southwestern Amazonia". The Auk. 107 (2): 239–245. doi:10.2307/4087605. ISSN 0004-8038. JSTOR 4087605.
- ^ Zimmer, Kevin J.; Whittaker, Andrew; Stotz, Douglas F. (1997). "Vocalizations, Behavior and Distribution of the Rio Branco Antbird". The Wilson Bulletin. 109 (4): 663–678. ISSN 0043-5643. JSTOR 4163867.
- ^ a b c d e f g h i j k l m n o p q Zimmer, J; Isler, L (1992). "Family Thamnophilidae (Typical antbirds)". In Del Hoyo, J; Del Hoyo, J; Elliott, A; Sargatal, J (eds.). Handbook of the birds of the world (1 ed.). Barcelona: Barcelona: Lynx edicions. ISBN 8487334105.
{{cite book}}: CS1 maint: publisher location (link) - ^ Irestedt, Martin; Fjeldså, Jon; Nylander, Johan AA; Ericson, Per GP (2004-07-30). "Phylogenetic relationships of typical antbirds (Thamnophilidae) and test of incongruence based on Bayes factors". BMC Evolutionary Biology. 4 (1). doi:10.1186/1471-2148-4-23. ISSN 1471-2148. PMC 509417. PMID 15283860.
- ^ Raposo, M.A.; Tello, J.G.; Dickinson, E.C.; Brito, G.R.R. (2015). "Remarks on the name Cercomacra Sclater, 1858 (Aves: Thamnophilidae) and its type species". Zootaxa. 3914 (1): 94–96. doi:10.11646/zootaxa.3914.1.9. PMID 25661931.
- ^ a b Zimmer, Kevin J.; Whittaker, Andrew; Stotz, Douglas F. (1997). "Vocalizations, Behavior and Distribution of the Rio Branco Antbird". The Wilson Bulletin. 109 (4): 663–678. ISSN 0043-5643. JSTOR 4163867.
- ^ Gill, Frank; Donsker, David, eds. (2018). "Antbirds". World Bird List Version 8.1. International Ornithologists' Union. Retrieved 30 January 2018.
- ^ a b c d e f g h i j k l m Willis, Edwin O. (1984). "Cercomacra and related antbirds (Aves, Formicariidae) as army ant followers". Revista Brasileira de Zoologia. 2 (7): 427–432. doi:10.1590/s0101-81751984000300003. ISSN 0101-8175.
- ^ a b Visco, Deborah M.; Sherry, Thomas W. (August 2015). "Increased abundance, but reduced nest predation in the chestnut-backed antbird in costa rican rainforest fragments: surprising impacts of a pervasive snake species". Biological Conservation. 188: 22–31. Bibcode:2015BCons.188...22V. doi:10.1016/j.biocon.2015.01.015.
- ^ a b c d e Avilés, Jesús M. (2024-01-03). "The evolutionary ecology of bird–ant interactions: a pervasive but under-studied connection". Proceedings of the Royal Society B: Biological Sciences. 291 (2014): 20232023. doi:10.1098/rspb.2023.2023. PMC 10762437. PMID 38166423.
- ^ Willson, Susan K. (2004). "Obligate Army-Ant-Following Birds: A Study of Ecology, Spatial Movement Patterns, and Behavior in Amazonian Peru". Ornithological Monographs (55): 1–67. doi:10.2307/40166802. ISSN 0078-6594. JSTOR 40166802.
- ^ a b IUCN (2024). "The IUCN Red List of Threatened Species". IUCN. Retrieved 28 March 2025.
- ^ a b c d e Lees, Alexander C.; Peres, Carlos A. (2010). "Habitat and Life History Determinants of Antbird Occurrence in Variable-Sized Amazonian Forest Fragments". Biotropica. 42 (5): 614–621. Bibcode:2010Biotr..42..614L. doi:10.1111/j.1744-7429.2010.00625.x. ISSN 1744-7429.
