Plain Antvireo
Encyclopedia
The Plain Antvireo, Dysithamnus mentalis, is a passerine
bird
species
in the antbird
family
(Thamnophilidae), wherein it belongs to the antshrike subfamily (Thamnophilinae). It is a resident breeder in tropical Central
and South America
.
Depending on subspecies
, there are large variations in the plumage
of both sexes, especially in the colour of the underparts (yellow to white), the darkness of the face, the amount of olive to the upperparts of the male, and the amount of rufous to the upperparts of the female.
It has a musical buu-bu-bu-bu-u-u-u song, and calls include a weak naaa and a questioning bu-u-u-u-u?
south to northern Argentina
, and on Trinidad
and Tobago
. It is patchily distributed at the margins of its range and generally (but not universally) avoids the lowlands.
In Guyana
for example, it is at least locally common above 1,000 meters ASL
in the Pakaraima Mountains (though not Mount Roraima), and also inhabits the southern Acari Mountains. On the other hand, it has not been recorded from the Iwokrama Forest
or the Potaro Plateau. In Nicaragua
where upland habitat is mainly restricted to the northwest, the species occurs only here and there in most of the country. For example, the Plain Antvireo was found to be common, a few dozen meters ASL, in the Dipteryx oleifera-dominated primary forest of Refugio Bartola in the very south of Nicaragua.
The Plain Antvireo feeds like a vireo
of the songbird
family
Vireonidae, hence its common name. It forages for small insect
s and other arthropod
s taken from twigs and foliage in the lower branches of trees. It usually does not join mixed-species feeding flock
s often, preferring to keep its distance from other species it encounters when attending army ant
swarms. Locally, however (e.g. as noted in the somewhat atypical habitat of Refugio Bartola), it may attend mixed-species flocks more frequently. But usually, it is encountered in pairs or small groups, such as adults with last years' young or birds congregating at a special food source. Breeding pairs are quite territorial against conspecifics however, and defend a patch of habitat that may be as large as about 7,000 square metres, but sometimes is only half that size.
The female lays two cinnamon-marked white eggs in a small deep cup nest in the lateral fork of a sapling. The eggs are incubated by both parents for 15 days to hatching, with a further 9 days to fledging. If the nest is approached, an incubating bird will drop to the ground and flutter weakly to distract the potential predator. During this, the light shoulder stripe is flashed conspicuously to attract the intruder's attention to the parent.
Due to its large range, this species is not considered threatened by the IUCN. It appears to be tolerant of some degree of habitat disturbance and/or human activity.
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in the antbird
Antbird
The antbirds are a large family, Thamnophilidae, of passerine birds found across subtropical and tropical Central and South America, from Mexico to Argentina. There are more than 200 species, known variously as antshrikes, antwrens, antvireos, fire-eyes, bare-eyes and bushbirds...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
(Thamnophilidae), wherein it belongs to the antshrike subfamily (Thamnophilinae). It is a resident breeder in tropical Central
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
.
Description
The Plain Antvireo is typically 11.4 cm long, and weighs 13.5 g. The adult male has a slate grey head and upperparts, blackish cheeks, three narrow white wing bars, pale grey underparts and a white belly. The female has olive brown upperparts, a rufous crown, a white eye-ring, yellowish-buff underparts and weakly buff-barred rufous wings. A white (male) or buff (female) shoulder stripe is only visible when the wing is spread. Immature males are much like the adult male, but have brown edgings to the flight feathers, an olive rump and yellowish underparts.Depending on subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, there are large variations in the plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
of both sexes, especially in the colour of the underparts (yellow to white), the darkness of the face, the amount of olive to the upperparts of the male, and the amount of rufous to the upperparts of the female.
It has a musical buu-bu-bu-bu-u-u-u song, and calls include a weak naaa and a questioning bu-u-u-u-u?
Ecology
This is a common and confiding bird of primary and secondary forest. The Plain Antvireo breeds from southern MexicoMexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
south to northern Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, and on Trinidad
Trinidad
Trinidad is the larger and more populous of the two major islands and numerous landforms which make up the island nation of Trinidad and Tobago. It is the southernmost island in the Caribbean and lies just off the northeastern coast of Venezuela. With an area of it is also the fifth largest in...
and Tobago
Tobago
Tobago is the smaller of the two main islands that make up the Republic of Trinidad and Tobago. It is located in the southern Caribbean, northeast of the island of Trinidad and southeast of Grenada. The island lies outside the hurricane belt...
. It is patchily distributed at the margins of its range and generally (but not universally) avoids the lowlands.
In Guyana
Guyana
Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...
for example, it is at least locally common above 1,000 meters ASL
Above mean sea level
The term above mean sea level refers to the elevation or altitude of any object, relative to the average sea level datum. AMSL is used extensively in radio by engineers to determine the coverage area a station will be able to reach...
in the Pakaraima Mountains (though not Mount Roraima), and also inhabits the southern Acari Mountains. On the other hand, it has not been recorded from the Iwokrama Forest
Iwokrama Forest
The Iwokrama Forest is nearly 3710 square kilometres of central Guyana located in the heart of the Guiana Shield, one of the four last pristine tropical forests in the world,...
or the Potaro Plateau. In Nicaragua
Nicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
where upland habitat is mainly restricted to the northwest, the species occurs only here and there in most of the country. For example, the Plain Antvireo was found to be common, a few dozen meters ASL, in the Dipteryx oleifera-dominated primary forest of Refugio Bartola in the very south of Nicaragua.
The Plain Antvireo feeds like a vireo
Vireo
The vireos are a group of small to medium-sized passerine birds restricted to the New World. They are typically dull-plumaged and greenish in color, the smaller species resembling wood warblers apart from their heavier bills...
of the songbird
Songbird
A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Vireonidae, hence its common name. It forages for small insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and other arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s taken from twigs and foliage in the lower branches of trees. It usually does not join mixed-species feeding flock
Mixed-species feeding flock
A mixed-species feeding flock, also termed a mixed-species foraging flock, mixed hunting party or informally bird wave, is a flock of usually insectivorous birds of different species, that join each other and move together while foraging...
s often, preferring to keep its distance from other species it encounters when attending army ant
Army ant
The name army ant is applied to over 200 ant species, in different lineages, due to their aggressive predatory foraging groups, known as "raids", in which huge numbers of ants forage simultaneously over a certain area, attacking prey en masse.Another shared feature is that, unlike most ant...
swarms. Locally, however (e.g. as noted in the somewhat atypical habitat of Refugio Bartola), it may attend mixed-species flocks more frequently. But usually, it is encountered in pairs or small groups, such as adults with last years' young or birds congregating at a special food source. Breeding pairs are quite territorial against conspecifics however, and defend a patch of habitat that may be as large as about 7,000 square metres, but sometimes is only half that size.
The female lays two cinnamon-marked white eggs in a small deep cup nest in the lateral fork of a sapling. The eggs are incubated by both parents for 15 days to hatching, with a further 9 days to fledging. If the nest is approached, an incubating bird will drop to the ground and flutter weakly to distract the potential predator. During this, the light shoulder stripe is flashed conspicuously to attract the intruder's attention to the parent.
Due to its large range, this species is not considered threatened by the IUCN. It appears to be tolerant of some degree of habitat disturbance and/or human activity.
Further reading
- ffrench, Richard; O'Neill, John Patton & Eckelberry, Don R. (1991): A guide to the birds of Trinidad and Tobago (2nd edition). Comstock Publishing, Ithaca, N.Y. ISBN 0-8014-9792-2
- Hilty, Steven L. (2003): Birds of Venezuela. Christopher HelmHelm Identification GuidesThe Helm Identification Guides are a series of books that identify groups of birds. The series include two types of guides, those that are:* Taxonomic, dealing with a particular family of birds on a worldwide scale—most early Helm Guides were this type, as well as many more-recent ones,...
, London. ISBN 0-7136-6418-5 - Stiles, F. Gary & Skutch, Alexander Frank (1989): A guide to the birds of Costa Rica. Comistock, Ithaca. ISBN 0-8014-9600-4