White-necked Thrush
Encyclopedia
The White-necked Thrush (Turdus albicollis) is a songbird
found in forest and woodland in South America
. The taxonomy
is potentially confusing, and it sometimes includes the members of the T. assimilis group as subspecies
, in which case the "combined species" is referred to as the White-throated Thrush (a name limited to T. assimilis when the two are split). On the contrary, it may be split into two species, the Rufous-flanked Thrush (T. albicollis) and the Grey-flanked Thrush (T. phaeopygos).
is 20½-26 cm (8-10 in) long and weighs 40-77 g (1.4-2.7 oz). The upperparts are dark brown, turning duskier or greyer towards the ocular region. The throat is white with dense dark streaks, except on the lowermost part, resulting in the appearance of a white crescent below the dark-streaked white throat. This has given rise to both its English
and scientific name. The crissum and central belly are whitish, and the chest is grey often tinged brown. The members of the nominate group have conspicuous rufous flanks, and the bill is yellow with a dusky culmen. The flanks are paler and more tawny in the subspecies crotopezus, which also has the entire upper mandible dusky. The members of the phaeopygos group lack contrasting rufous or tawny flanks, and have bills that are almost entirely dusky. All subspecies have pinkish-brown legs and a reddish or yellow eye-ring. Sexes are similar, but juveniles
are duller, with dull orange spotting above, and brownish spotting below.
The song is a relatively musical, often rather monotonous two-e-o, two-e. The calls is a distinctive wuk, while the alarm is a rough jjig-wig-wig.
, far northern Uruguay
, eastern Paraguay
and far north-eastern Argentina
. The phaeopygos group (including subspecies phaopygoides, spodiolaemus and contemptus) is mainly found in the Amazon Basin
, but with populations extending along the eastern slope of the Andes
as far south as north-eastern Argentina, and as far north as western Venezuela
, with extensions along the Coastal Range
, the region centered around Serranía del Perijá
and Sierra Nevada de Santa Marta
, and the islands of Trinidad and Tobago
.
Both groups are mainly associated with humid forest and woodland. In the case of the nominate group, mainly the Atlantic Forest, and in the case of the phaeopygos group, mainly the Amazon Rainforest
or humid forests and woodlands near mountains. It rarely ventures far from cover.
s. It also takes some fruit
and berries
. It regularly follows army ant
swarms, but does not attend mixed species flocks. Throughout most of its range, especially in the Amazon, it is a shy species, heard far more than seen, but in Trinidad
and parts of south-eastern Brazil it may be less retiring.
The nest is a lined cup of twigs placed low (at a height of 1-9 m [3-30 ft]) in a tree or bush. Two to three reddish-blotched green-blue eggs are laid and incubated by the female alone for 12-13 days.
On the contrary, it has been suggested that the nominate group and the phaeopygos group of T. albicollis should be considered separate species, but the voices of the two are similar, and the subspecies crotopezus from the nominate group approach members of the phaeopygos group in both plumage and colour of bill. If the two groups are split, the common name
Rufous-flanked Thrush has been suggested for T. albicollis, with T. phaeopygos retaining the common name White-necked Thrush or being renamed Grey-flanked Thrush.
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"...
found in forest and woodland in 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...
. The taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
is potentially confusing, and it sometimes includes the members of the T. assimilis group as 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...
, in which case the "combined species" is referred to as the White-throated Thrush (a name limited to T. assimilis when the two are split). On the contrary, it may be split into two species, the Rufous-flanked Thrush (T. albicollis) and the Grey-flanked Thrush (T. phaeopygos).
Description
This thrushThrush (bird)
The thrushes, family Turdidae, are a group of passerine birds that occur worldwide.-Characteristics:Thrushes are plump, soft-plumaged, small to medium-sized birds, inhabiting wooded areas, and often feed on the ground or eat small fruit. The smallest thrush may be the Forest Rock-thrush, at and...
is 20½-26 cm (8-10 in) long and weighs 40-77 g (1.4-2.7 oz). The upperparts are dark brown, turning duskier or greyer towards the ocular region. The throat is white with dense dark streaks, except on the lowermost part, resulting in the appearance of a white crescent below the dark-streaked white throat. This has given rise to both its English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
and scientific name. The crissum and central belly are whitish, and the chest is grey often tinged brown. The members of the nominate group have conspicuous rufous flanks, and the bill is yellow with a dusky culmen. The flanks are paler and more tawny in the subspecies crotopezus, which also has the entire upper mandible dusky. The members of the phaeopygos group lack contrasting rufous or tawny flanks, and have bills that are almost entirely dusky. All subspecies have pinkish-brown legs and a reddish or yellow eye-ring. Sexes are similar, but juveniles
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
are duller, with dull orange spotting above, and brownish spotting below.
The song is a relatively musical, often rather monotonous two-e-o, two-e. The calls is a distinctive wuk, while the alarm is a rough jjig-wig-wig.
Distribution and habitat
The nominate group (including subspecies paraguayensis and crotopezus) occurs in eastern BrazilBrazil
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...
, far northern Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
, eastern Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...
and far north-eastern 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...
. The phaeopygos group (including subspecies phaopygoides, spodiolaemus and contemptus) is mainly found in the Amazon Basin
Amazon Basin
The Amazon Basin is the part of South America drained by the Amazon River and its tributaries that drains an area of about , or roughly 40 percent of South America. The basin is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela...
, but with populations extending along the eastern slope of the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
as far south as north-eastern Argentina, and as far north as western 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...
, with extensions along the Coastal Range
Venezuelan Coastal Range
The Venezuelan Coastal Range is a mountain range that runs along the central and eastern portions of Venezuela's northern coast...
, the region centered around Serranía del Perijá
Serrania del Perija
The Serranía del Perijá, Cordillera de Perijá or Sierra de Perijá is a mountain range, an extension of the eastern Andean branch , in northern South America, between Colombia and Venezuela, ending further north in the Guajira Desert, a total distance of about 310 km...
and Sierra Nevada de Santa Marta
Sierra Nevada de Santa Marta
The Sierra Nevada de Santa Marta is an isolated mountain range apart from the Andes chain that runs through Colombia. Reaching an altitude of 5,700 metres above sea level just 42 km from the Caribbean coast, the Sierra Nevada is the world's highest coastal range...
, and the islands of Trinidad and Tobago
Trinidad and Tobago
Trinidad and Tobago officially the Republic of Trinidad and Tobago is an archipelagic state in the southern Caribbean, lying just off the coast of northeastern Venezuela and south of Grenada in the Lesser Antilles...
.
Both groups are mainly associated with humid forest and woodland. In the case of the nominate group, mainly the Atlantic Forest, and in the case of the phaeopygos group, mainly the Amazon Rainforest
Amazon Rainforest
The Amazon Rainforest , also known in English as Amazonia or the Amazon Jungle, is a moist broadleaf forest that covers most of the Amazon Basin of South America...
or humid forests and woodlands near mountains. It rarely ventures far from cover.
Behavior
The White-necked Thrush mainly feeds on or near the ground on invertebrateInvertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s. It also takes some fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
and berries
Berry
The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....
. It regularly follows 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, but does not attend mixed species flocks. Throughout most of its range, especially in the Amazon, it is a shy species, heard far more than seen, but in 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 parts of south-eastern Brazil it may be less retiring.
The nest is a lined cup of twigs placed low (at a height of 1-9 m [3-30 ft]) in a tree or bush. Two to three reddish-blotched green-blue eggs are laid and incubated by the female alone for 12-13 days.
Taxonomy
T. albicollis sometimes includes the members of the T. assimilis group as subspecies, in which case the "combined species" is referred to as the White-throated Thrush (a name limited to T. assimilis when the two are split). Published evidence supporting either treatment is weak, but most recent authorities have followed the split.On the contrary, it has been suggested that the nominate group and the phaeopygos group of T. albicollis should be considered separate species, but the voices of the two are similar, and the subspecies crotopezus from the nominate group approach members of the phaeopygos group in both plumage and colour of bill. If the two groups are split, the common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
Rufous-flanked Thrush has been suggested for T. albicollis, with T. phaeopygos retaining the common name White-necked Thrush or being renamed Grey-flanked Thrush.
External links
- Turdus albicollis, "White-necked Robin" videos on the Internet Bird Collection
- White-necked Thrush photo gallery VIREO Photo-High Res
- Photo-High Res; Article oiseaux
