Yellow-legged Thrush
Encyclopedia
The Yellow-legged Thrush (Platycichla flavipes) is a songbird
of northern and eastern South America
. In recent times, it is increasingly often placed in the genus
Turdus again.
is usually black with a slate-grey back and lower underparts. However, the hue of the grey areas varies, and the male of one of the five subspecies
, P. f. xanthoscelus of Tobago
, is all-black, resembling the male Eurasian Blackbird (Turdus merula). Females have a dull bill, warm brown upperparts and paler underparts. The juvenile
male is brownish with black wings and tail, while the juvenile female resemble the adult
female, but is duller, flecked with orange above and spotted and barred with dark brown below.
The song of the male is musical phrases, sreep, sreee, sree, sreee, again somewhat resembling that of the Eurasian Blackbird, but sometimes including some imitation of other birds songs. The typical call is a sharp srip and a peculiar seeet given in alarm.
. One population breeds in northern Colombia
, Venezuela
, far northern Brazil
, Trinidad
, and Tobago
, as well as parts of the Pakaraima Mountains in western Guyana
(including as it seems Mount Roraima). A second population occurs in eastern Brazil
, eastern Paraguay
, and far northeastern Argentina
. The Argentine subpopulation is partially migratory
, being resident in the northern part, while southernmost breeders spend the Austral
winter further north. Some populations in northern South America
also take part in local movements, but these are not well understood.
The habitat of this small thrush is rainforest
, secondary woodland
, and overgrown plantations. It is mainly a species
of highlands
up to 2000 m (6,561.7 ft) ASL
, but locally it occurs down to near sea level
. The Yellow-legged Thrush mainly feeds in trees and bushes, infrequently on the ground, and mostly eats fruit
s and berries, e.g., Melastomataceae
. It rarely if ever attends mixed-species feeding flock
s, as its habit of keeping to the tree-tops makes it rarely worthwhile to join such conspicuous groups.
The nest is a lined shallow cup of twigs on a bank or amongst rocks. Two or three reddish-blotched green or blue eggs are laid.
It is fairly common in most of its range, and therefore listed as Least Concern
by the IUCN. However, the Yellow-legged Thrush is a shy species, and the female in particular is difficult to see, since she does not sing and has a cryptic
coloration.
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"...
of northern and eastern 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...
. In recent times, it is increasingly often placed in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Turdus again.
Description
This thrush is 22–23 cm (8.7–9.1 in) long and weighs 55–70 g (1.9–2.5 oz). Both sexes have yellow legs and eye-ring. The male has a yellow bill and its plumagePlumage
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...
is usually black with a slate-grey back and lower underparts. However, the hue of the grey areas varies, and the male of one of the five 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...
, P. f. xanthoscelus of 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...
, is all-black, resembling the male Eurasian Blackbird (Turdus merula). Females have a dull bill, warm brown upperparts and paler underparts. The juvenile
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...
male is brownish with black wings and tail, while the juvenile female resemble the adult
Adult
An adult is a human being or living organism that is of relatively mature age, typically associated with sexual maturity and the attainment of reproductive age....
female, but is duller, flecked with orange above and spotted and barred with dark brown below.
The song of the male is musical phrases, sreep, sreee, sree, sreee, again somewhat resembling that of the Eurasian Blackbird, but sometimes including some imitation of other birds songs. The typical call is a sharp srip and a peculiar seeet given in alarm.
Distribution and ecology
It has a highly disjunct distributionDisjunct distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...
. One population breeds in northern 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...
, 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...
, far northern 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...
, 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...
, as well as parts of the Pakaraima Mountains in western 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...
(including as it seems Mount Roraima). A second population occurs in eastern 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...
, 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 northeastern 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 Argentine subpopulation is partially migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
, being resident in the northern part, while southernmost breeders spend the Austral
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
winter further north. Some populations in northern 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...
also take part in local movements, but these are not well understood.
The habitat of this small thrush is rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
, secondary woodland
Secondary forest
A secondary forest is a forest or woodland area which has re-grown after a major disturbance such as fire, insect infestation, timber harvest or windthrow, until a long enough period has passed so that the effects of the disturbance are no longer evident...
, and overgrown plantations. It is mainly a 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...
of highlands
Highland (geography)
The term highland or upland is used to denote any mountainous region or elevated mountainous plateau. Generally speaking, the term upland tends to be used for ranges of hills, typically up to 500-600m, and highland for ranges of low mountains.The Scottish Highlands refers to the mountainous...
up to 2000 m (6,561.7 ft) 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...
, but locally it occurs down to near sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
. The Yellow-legged Thrush mainly feeds in trees and bushes, infrequently on the ground, and mostly eats 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,...
s and berries, e.g., Melastomataceae
Melastomataceae
right|thumb|200px|Characteristic venation of many melastomesThe family Melastomataceae is a taxon of dicotyledonous flowering plants found mostly in the tropics comprising some 200 genera and 4500 species...
. It rarely if ever attends 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, as its habit of keeping to the tree-tops makes it rarely worthwhile to join such conspicuous groups.
The nest is a lined shallow cup of twigs on a bank or amongst rocks. Two or three reddish-blotched green or blue eggs are laid.
It is fairly common in most of its range, and therefore listed as Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
by the IUCN. However, the Yellow-legged Thrush is a shy species, and the female in particular is difficult to see, since she does not sing and has a cryptic
Crypsis
In ecology, crypsis is the ability of an organism to avoid observation or detection by other organisms. It may be either a predation strategy or an antipredator adaptation, and methods include camouflage, nocturnality, subterranean lifestyle, transparency, and mimicry...
coloration.