White-fringed Antwren
Encyclopedia
The White-fringed Antwren, Formicivora grisea, is a passerine
bird
in the antbird
family. It is a resident breeder in tropical South America
from Colombia
southeast to the Guianas
and Brazil
, and on Tobago
.
The White-fringed Antwren is typically 12.7 cm long, and weighs 9.4 g. The male has a grey-brown crown and upperparts, and black wings, tail, lower face and underparts. There are two conspicuous white wing bars and a white stripe running from above the eye down the sides of the breast and flanks. The tail feathers are tipped with white. The female's upperparts are much like the male, but females of the southern populations are orange below and have an orange supercilium
. These occur south and east from southeastern Colombia and southernmost Venezuela
. Northern population's females have underparts which are buff with dark streaks. The Tobagonian subspecies
F. g. tobagensis is larger than mainland birds.
It has a tu whistle followed by a trilled churet, and a repeated and accelerating tu-ik call. Southern birds also have a repetitive chump-chump-chump song, quite unlike northern races which are sometimes separated as Northern White-fringed Antwren (Formicivora intermedia). F. grisea proper would then become the Southern White-fringed Antwren.
This is a common and confiding bird of second growth woodland, usually found as territorial pairs. The southern populations are associated with scrubby bushes on white sandy soils and restinga
habitat. These birds inhabit the lowlands, up to around 200 meters ASL
. In some places, they are sympatric with the Rusty-backed Antwren
(F. rufa). The White-fringed Antwren feeds on small insect
s and other arthropod
s taken from undergrowth twigs and foliage.
The female lays two purple-marked creamy white eggs, which are incubated by both sexes, in a grass hammock nest low in a tree or shrub. Nests are occasionally plundered by predators, for example smallish mammal
s like the Common Marmoset
(Callithrix jacchus), despite the birds' attempts to defend their offspring.
Of a total of 13 birds studied in Colombia
– in the Parque Nacional de La Macarena and near Turbo
–, only one was infected with blood parasite
s (an undetermined Plasmodium
species).
This bird is not considered globally threatened by the IUCN. However, its resilience to human alteration of habitat is not too pronounced, and in some regions its continuing presence would seem to depend on protection of habitat.
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...
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. It is a resident breeder in tropical 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...
from Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
southeast to the Guianas
The Guianas
The Guyanas or the Guianas refers to a region in north-eastern South America which includes the following three territories:* French Guiana, an overseas department of France;...
and Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, and on 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...
.
The White-fringed Antwren is typically 12.7 cm long, and weighs 9.4 g. The male has a grey-brown crown and upperparts, and black wings, tail, lower face and underparts. There are two conspicuous white wing bars and a white stripe running from above the eye down the sides of the breast and flanks. The tail feathers are tipped with white. The female's upperparts are much like the male, but females of the southern populations are orange below and have an orange supercilium
Supercilium
The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head. Also known as an "eyebrow", it is distinct from the eyestripe, which is a line which runs...
. These occur south and east from southeastern Colombia and southernmost Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
. Northern population's females have underparts which are buff with dark streaks. The Tobagonian 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...
F. g. tobagensis is larger than mainland birds.
It has a tu whistle followed by a trilled churet, and a repeated and accelerating tu-ik call. Southern birds also have a repetitive chump-chump-chump song, quite unlike northern races which are sometimes separated as Northern White-fringed Antwren (Formicivora intermedia). F. grisea proper would then become the Southern White-fringed Antwren.
This is a common and confiding bird of second growth woodland, usually found as territorial pairs. The southern populations are associated with scrubby bushes on white sandy soils and restinga
Restinga
Restinga is a municipality in the state of São Paulo in Brazil. The population in 2004 was 6,188 and the area is 246.37 km². The elevation is 910 m....
habitat. These birds inhabit the lowlands, up to around 200 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 some places, they are sympatric with the Rusty-backed Antwren
Rusty-backed Antwren
The Rusty-backed Antwren is a species of bird in the Thamnophilidae family.It is found in Bolivia, Brazil, Paraguay, Peru, and Suriname....
(F. rufa). The White-fringed Antwren feeds on 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 undergrowth twigs and foliage.
The female lays two purple-marked creamy white eggs, which are incubated by both sexes, in a grass hammock nest low in a tree or shrub. Nests are occasionally plundered by predators, for example smallish mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s like the Common Marmoset
Common Marmoset
The common marmoset is a New World monkey. It originally lived on the Northeastern coast of Brazil, in the states of Piaui, Paraiba, Ceará, Rio Grande do Norte, Pernambuco, Alagoas and Bahia...
(Callithrix jacchus), despite the birds' attempts to defend their offspring.
Of a total of 13 birds studied in Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
– in the Parque Nacional de La Macarena and near Turbo
Turbo, Colombia
Turbo is a port town in Antioquia Department, Colombia. It is located at around . It is located on the coast of Gulf of Urabá, 340 km. north from Medellín...
–, only one was infected with blood parasite
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
s (an undetermined Plasmodium
Plasmodium
Plasmodium is a genus of parasitic protists. Infection by these organisms is known as malaria. The genus Plasmodium was described in 1885 by Ettore Marchiafava and Angelo Celli. Currently over 200 species of this genus are recognized and new species continue to be described.Of the over 200 known...
species).
This bird is not considered globally threatened by the IUCN. However, its resilience to human alteration of habitat is not too pronounced, and in some regions its continuing presence would seem to depend on protection of habitat.
External links
- Formicivora grisea photos on Flickr