Common Bush-Tanager
Encyclopedia
The Common Bush-tanager (Chlorospingus ophthalmicus) is a small passerine
bird
. It is a resident breeder in the highlands from central Mexico
south to Bolivia
and northwest Argentina
. C. ophthalmicus in the loose sense is a notorious cryptic species complex
, and several of the up to 25 subspecies
recognized in recent times are likely to be distinct species
. Some populations in fact appear to be more distinct than several other members of Chlorospingus
.
and a white spot behind the eye and a light throat. The upperparts are olive and the underparts yellow, becoming white on the belly. Coloration, especially of the cheeks, throat and eye region, is very variable across the wide range, giving weight to the theory that this these birds form a superspecies
. Immatures are browner above, darker below, and have a duller olive eye spot. Hatchlings are covered in dark grey down feather
s and have bright yellow bills.
The call is a squeaky tseeet or chit. Songs vary widely between the populations.
The related Sooty-capped Bush-tanager
(C. pileatus) has a blacker head with a bold white supercilium
rather than an eye spot.
This bird is typically found from 400 m to 2,300 m ASL
in Middle America
; near the Equator
they are common found at altitudes of 2,000-3,500 m ASL. Its habitat
– cloud forest
s with ample undergrowth
and adjacent bushy clearings – is dominated by trees and shrubs from such families
as Asteraceae
, Clusiaceae
, Cyatheaceae
, Melastomataceae
, Rubiaceae
and Winteraceae
, and epiphyte
s of the Araceae
(e.g. Anthurium
) and Orchidaceae
.
The Common Bush-tanager is usually encountered in small groups or as part of a mixed-species feeding flock
, and is rather sedentary. This passerine feeds on insect
s, spider
s small fruit
s and nectar.
The menoponid
chewing louse
Myrsidea ophthalmici was described from a Venezuela
n specimen of this bird; it is not known from other hosts to date. The Venezuelan population of the Common Bush-tanager would, if this taxon
is split up, be assigned to a distinct species.
There is apparently no dedicated nesting season at least in the hottest parts of its range, but in general it seems that the Common Bush-tanager prefers to breed mainly between October and May. These birds hide their nest below vegetation on a bank or slope, in a hollow or tree trunk, amongst epiphytes, or up in a tree. The bulky cup nest, made from thin twigs and roots, coarse leaves and mosses, is some 10–15 cm high and nearly 10 cm wide. The nest cup, lined with fine leaves and fibers, is almost 5 cm wide and deep. The nest may be placed over 20 meters up in a tree, but usually is located 15 m high or less; in most populations nests are occasionally built less than one meter above and sometimes even right on the ground.
The normal clutch
is two eggs in most of the range. The northernmost populations, however, seem to produce clutches of three eggs not infrequently, while in the southern Andean group one-egg clutches might be frequent or even the norm. This species is regularly double-brooded at least in part of its range. The eggs are off-white and marked with larger puce
and smaller maroon
spots mainly on the blunt end. They are about 20 mm long and weigh about 2.4 g on average, though eggs in one-egg clutches of Andean birds may measure almost 24 mm in length and normally weigh around 3 g, but occasionally more than 3.5 g. The female incubates for much of the day, while both parents provide the young with food. As the nestlings near fledging, they are fed every 15 minutes or so on average.
family
, Thraupidae. More recent research suggests that they are actually aberrant brush-finches in the Emberizidae
and particularly close to Arremonops
. Hence, as a common name "chlorospinguses" would arguably better than that the widely used "brush-tanagers", as the former is equally well suited to either placement.
The wide range and considerable morphological
variation displayed by C. ophthalmicus has been a problem for ornithologists for many decades. Initially, many taxa presently united in this species
were considered distinct, but they were eventually all lumped together. More recent results suggest that the "Common Bush-tanager" is actually a superspecies
.
A preliminary study of allozyme
data found pronounced divergences between the northern populations. mtDNA ATPase
8 sequence
data found 5 major clade
s in the Mexican populations alone. These were subsequently confirmed by morphological comparisons. A formal splitting-up of this species into several seems to be the eventual outcome, pending data from the populations south of Mexico. In addition, it would be interesting to determine whether there are geographical variations in the song that would further strengthen the case for species status of the taxa. The morphological variation, though recognizable, is rather inconspicuous and probably more the consequence of genetic drift
in freshly isolated subpopulations than a cause for their separation.
It appears as if the group north of the Isthmus of Panama
originated before the final bout of the Great American Interchange
, by island-hopping across the emerging mountain ranges that now make up the isthmus, some 6 million years ago (mya). The direct descendants of the original colonizers of Mesoamerica
are the southernmost Mesoamerican group, as is to be expected. Some 5.5 mya, the Sierra de los Tuxtlas
population originated. The other groups west of the Isthmus of Tehuantepec
radiated
rather synchronously between 3 and 4 mya.
Notably, the divergence between the northern clades seems to have occurred far too early for the Pleistocene
ice age
s to have played a major part. Rather, it appears that the "Common Bush-tanager" evolve
d in and was always confined to montane cloud forest. Given its sedentary habits, the phylogeny seems to be a result of a combination of habitat expanding and constricting due to Pliocene climate
changes and, less frequently, accidental dispersal (such as to the Sierra de los Tuxtlas and, earlier, to Mesoamerica in general).
The 5 northern clades are:
Chlorospingus ophthalmicus regionalis is found in Costa Rica
. Its relationship to the postocularis group and the Panama
nian C. o. novicius warrants thorough study, as these three taxa appear to be rather intermediate between the main northern and the South America
n groups, with whitish ears but a fairly brownish crown.
In the north of the Cordillera Oriental
of Colombia
, extending into the Cordillera de Mérida
and Serranía del Perijá
of Venezuela
, a group of subspecies occurs that resembles the northernly birds; subspecies such as C. o. venezuelensis are included here. They might be most closely related to those around the Isthmus of Panama, or constitute a group distinct from the Central American forms. An undetermined and possibly new subspecies is found in Lara state in Venezuela, for example in Yacambú National Park. C. o. jacqueti occurs in Norte de Santander and possibly Boyacá
and Santander
departments in Colombia
; it seems to be the most southernly representative of this group. These birds have a greyish-brown crown, a buffy-white speckled throat, and – like the birds further north – a white ear region. Their dawn song consists of a monotonous series of chit or chup notes.
Between Norte de Santander and the border region of Antioquia
, Boyacá, Cundinamarca
and Santander departments, a complex situation exists, with C. o. eminens, C. o. exitelus and C. o. trudis being of unclear assignment as to subspecies group. If there is little intergradation in this region, the case for the southern Andean populations being a distinct species is rather robust. In fact, they have time and again been treated as a good species C. flavopectus.
The flavopectus group contains larger birds which lack a pronounced brown tinge on the crown; many members have this area purely grey to blackish. The white throat is almost devoid of spotting, and there is no white ear spot. This group includes taxa such as C. o. flavopectus and C. o. nigriceps from central to southern Colombia, C. o. phaeocephalus from Ecuador
, C. o. peruvianus from Peru
, or C. o. cinereocephalus and C. o. hiaticolus. Their dawn song consists of a series of chit notes, accelerating to higher-pitched chit-its and often accelerating further but descending in putch again to fade out in a churring trill trrrrrrrr.... Some, like C. o. phaeocephalus and C. o. nigriceps, have an even more complex dawn song, in which the middle part is replaced by a first trill at constant volume, breaking up into a few shorter trills trrrrrrrr tr tr tr... before ending with the fading lower trill. These populations also tend to give long series of chit calls between their songs.
In the far south of the species' range, C. o. argentatus is found in the yungas
of northwestern Argentina
. It is not known exactly how these birds relate to the taxa higher up in the Andes; they are generally little-studied. They have a tendency to build their nests uncharacteristically high up in trees; for this reason, it is unknown whether one-egg clutches are as commonly seen in this population as they seem to occur in the flavopectus group. It does not seem to like nesting less than 10 meters above the ground, but considering the high rate of failed nesting attempts (more than 35% abandoned nests in one study in El Rey National Park
), avoiding predators or other reasons for brood failure does not seem to be a very good explanation for this behavior.
47: 650–664
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...
. It is a resident breeder in the highlands from central Mexico
Mexico
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 Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
and northwest 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...
. C. ophthalmicus in the loose sense is a notorious cryptic species complex
Cryptic species complex
In biology, a cryptic species complex is a group of species which satisfy the biological definition of species—that is, they are reproductively isolated from each other—but whose morphology is very similar ....
, and several of the up to 25 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...
recognized in recent times are likely to be distinct 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...
. Some populations in fact appear to be more distinct than several other members of Chlorospingus
Chlorospingus
Chlorospingus, the bush-tanagers, are a genus of perching birds traditionally placed in the tanager family . This seems in error according to more recent studies, which suggest that they are closely related to the genus Arremonops in the Emberizidae...
.
Description and ecology
The adult is 13.5 cm long and weighs 20 g on average. They have a brown head with a (usually) thin superciliumSupercilium
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...
and a white spot behind the eye and a light throat. The upperparts are olive and the underparts yellow, becoming white on the belly. Coloration, especially of the cheeks, throat and eye region, is very variable across the wide range, giving weight to the theory that this these birds form a superspecies
Superspecies
A superspecies is a group of at least two more or less distinctive species with approximately parapatric distributions. Not all species complexes, whether cryptices or ring species are superspecies, and vice versa, but many are...
. Immatures are browner above, darker below, and have a duller olive eye spot. Hatchlings are covered in dark grey down feather
Down feather
The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator and padding, used in goods such as jackets, bedding,...
s and have bright yellow bills.
The call is a squeaky tseeet or chit. Songs vary widely between the populations.
The related Sooty-capped Bush-tanager
Sooty-capped Bush-Tanager
The Sooty-capped Bush-Tanager, Chlorospingus pileatus, is a small passerine bird. This tanager is an endemic resident breeder in the highlands of Costa Rica and western Panama....
(C. pileatus) has a blacker head with a bold white 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...
rather than an eye spot.
This bird is typically found from 400 m to 2,300 m 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 Middle America
Middle America (Americas)
Middle America is a region in the mid-latitudes of the Americas. In southern North America, it usually comprises Mexico, the nations of Central America, and the West Indies. The scope of the term may vary...
; near the Equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
they are common found at altitudes of 2,000-3,500 m ASL. Its habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
– cloud forest
Cloud forest
A cloud forest, also called a fog forest, is a generally tropical or subtropical evergreen montane moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests often exhibit an abundance of mosses covering the ground and...
s with ample undergrowth
Undergrowth
Undergrowth usually refers to the vegetation in a forest, which can obstruct passage through the forest. The height of undergrowth is usually considered to be 0.3 – 3 m . Undergrowth can also refer all vegetation in a forest, which isn't in the canopy....
and adjacent bushy clearings – is dominated by trees and shrubs from such families
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...
as Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
, Clusiaceae
Clusiaceae
The Clusiaceae or Guttiferae Juss. is a family of plants formerly including about 37 genera and 1610 species of trees and shrubs, often with milky sap and fruits or capsules for seeds. It is primarily tropical...
, Cyatheaceae
Cyatheaceae
The Cyatheaceae is the scaly tree fern family and includes the world's tallest tree ferns, which reach heights up to 20 m. They are also very ancient plants, appearing in the fossil record in the late Jurassic, though the modern genera likely appeared in the Tertiary. Cyatheaceae is the largest...
, 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...
, Rubiaceae
Rubiaceae
The Rubiaceae is a family of flowering plants, variously called the coffee family, madder family, or bedstraw family. The group contains many commonly known plants, including the economically important coffee , quinine , and gambier , and the horticulturally valuable madder , west indian jasmine ,...
and Winteraceae
Winteraceae
The Winteraceae are a family of flowering plants. The family includes 120 species of trees and shrubs in 9 genera.The Winteraceae are a mostly southern-hemisphere family associated with the Antarctic flora, found in tropical to temperate climate regions of Malesia, Oceania, eastern Australia, New...
, and epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
s of the Araceae
Araceae
Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe or leaf-like bract. Also known as the Arum family, members are often colloquially...
(e.g. Anthurium
Anthurium
Anthurium , is a large genus of about 600–800 species, belonging to the arum family . Anthurium can also be called "Flamingo Flower" or "Boy Flower", both referring to the structure of the spathe and spadix....
) and Orchidaceae
Orchidaceae
The Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...
.
The Common Bush-tanager is usually encountered in small groups or as part of a 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...
, and is rather sedentary. This passerine feeds on 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, spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s small 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 nectar.
The menoponid
Menoponidae
Sometimes referred to as the chicken body louse family, the Menoponidae are a family of a larger group Amblycera of the chewing lice. Most commonly they are ectoparasites of a wide range of birds....
chewing louse
Chewing louse
Mallophaga is a suborder of lice, known as chewing lice, biting lice or bird lice, containing more than 3000 species. They have paurometabolis or incomplete metamorphosis....
Myrsidea ophthalmici was described from a 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...
n specimen of this bird; it is not known from other hosts to date. The Venezuelan population of the Common Bush-tanager would, if this taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
is split up, be assigned to a distinct species.
There is apparently no dedicated nesting season at least in the hottest parts of its range, but in general it seems that the Common Bush-tanager prefers to breed mainly between October and May. These birds hide their nest below vegetation on a bank or slope, in a hollow or tree trunk, amongst epiphytes, or up in a tree. The bulky cup nest, made from thin twigs and roots, coarse leaves and mosses, is some 10–15 cm high and nearly 10 cm wide. The nest cup, lined with fine leaves and fibers, is almost 5 cm wide and deep. The nest may be placed over 20 meters up in a tree, but usually is located 15 m high or less; in most populations nests are occasionally built less than one meter above and sometimes even right on the ground.
The normal clutch
Clutch (eggs)
A clutch of eggs refers to all the eggs produced by birds or reptiles, often at a single time, particularly those laid in a nest.In birds, destruction of a clutch by predators, , results in double-clutching...
is two eggs in most of the range. The northernmost populations, however, seem to produce clutches of three eggs not infrequently, while in the southern Andean group one-egg clutches might be frequent or even the norm. This species is regularly double-brooded at least in part of its range. The eggs are off-white and marked with larger puce
Puce
Puce is a color that is defined as ranging from reddish-brown to purplish-brown, with the latter being the more widely accepted definition found in reputable sources. Puce is a shade of red. The Oxford English Dictionary dates the use of "puce" from 1787...
and smaller maroon
Maroon (color)
Maroon is a dark red color.-Etymology:Maroon is derived from French marron .The first recorded use of maroon as a color name in English was in 1789.-Maroon :...
spots mainly on the blunt end. They are about 20 mm long and weigh about 2.4 g on average, though eggs in one-egg clutches of Andean birds may measure almost 24 mm in length and normally weigh around 3 g, but occasionally more than 3.5 g. The female incubates for much of the day, while both parents provide the young with food. As the nestlings near fledging, they are fed every 15 minutes or so on average.
Systematics and taxonomy
Traditionally, the genus Chlorospingus was placed with the tanagerTanager
The tanagers comprise the bird family Thraupidae, in the order Passeriformes. The family has an American distribution.There were traditionally about 240 species of tanagers, but the taxonomic treatment of this family's members is currently in a state of flux...
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...
, Thraupidae. More recent research suggests that they are actually aberrant brush-finches in the Emberizidae
Emberizidae
The Emberizidae are a large family of passerine birds. They are seed-eating birds with a distinctively shaped bill.In Europe, most species are called buntings. In North America, most of the species in this family are known as sparrows, but these birds are not closely related to the sparrows, the...
and particularly close to Arremonops
Arremonops
Arremonops is a genus of neotropical birds in the Emberizidae family. All species are found in Central America, Mexico, and/or northern South America...
. Hence, as a common name "chlorospinguses" would arguably better than that the widely used "brush-tanagers", as the former is equally well suited to either placement.
The wide range and considerable morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
variation displayed by C. ophthalmicus has been a problem for ornithologists for many decades. Initially, many taxa presently united in this 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...
were considered distinct, but they were eventually all lumped together. More recent results suggest that the "Common Bush-tanager" is actually a superspecies
Superspecies
A superspecies is a group of at least two more or less distinctive species with approximately parapatric distributions. Not all species complexes, whether cryptices or ring species are superspecies, and vice versa, but many are...
.
A preliminary study of allozyme
Allozyme
Variant forms of an enzyme that are coded by different alleles at the same locus are called allozymes. These are opposed to isozymes, which are enzymes that perform the same function, but which are coded by genes located at different loci....
data found pronounced divergences between the northern populations. mtDNA ATPase
ATPase
ATPases are a class of enzymes that catalyze the decomposition of adenosine triphosphate into adenosine diphosphate and a free phosphate ion. This dephosphorylation reaction releases energy, which the enzyme harnesses to drive other chemical reactions that would not otherwise occur...
8 sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data found 5 major clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
s in the Mexican populations alone. These were subsequently confirmed by morphological comparisons. A formal splitting-up of this species into several seems to be the eventual outcome, pending data from the populations south of Mexico. In addition, it would be interesting to determine whether there are geographical variations in the song that would further strengthen the case for species status of the taxa. The morphological variation, though recognizable, is rather inconspicuous and probably more the consequence of genetic drift
Genetic drift
Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
in freshly isolated subpopulations than a cause for their separation.
Northern group
These populations are characterized by a crown which is more brownish than grey, and in some even a pure hue of more or less reddish brown. The head markings are usually conspicuous and contrasting. Their song is a high thin whichis whichis witchery tsee tseep seeur with many variations.It appears as if the group north of the Isthmus of Panama
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...
originated before the final bout of the Great American Interchange
Great American Interchange
The Great American Interchange was an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents...
, by island-hopping across the emerging mountain ranges that now make up the isthmus, some 6 million years ago (mya). The direct descendants of the original colonizers of Mesoamerica
Mesoamerica
Mesoamerica is a region and culture area in the Americas, extending approximately from central Mexico to Belize, Guatemala, El Salvador, Honduras, Nicaragua, and Costa Rica, within which a number of pre-Columbian societies flourished before the Spanish colonization of the Americas in the 15th and...
are the southernmost Mesoamerican group, as is to be expected. Some 5.5 mya, the Sierra de los Tuxtlas
Sierra de los Tuxtlas
The Sierra de Los Tuxtlas are a volcanic belt and mountain range along the southeastern Veracruz Gulf coast in southcentral Mexico....
population originated. The other groups west of the Isthmus of Tehuantepec
Isthmus of Tehuantepec
The Isthmus of Tehuantepec is an isthmus in Mexico. It represents the shortest distance between the Gulf of Mexico and the Pacific Ocean, and prior to the opening of the Panama Canal was a major shipping route known simply as the Tehuantepec Route...
radiated
Evolutionary radiation
An evolutionary radiation is an increase in taxonomic diversity or morphological disparity, due to adaptive change or the opening of ecospace. Radiations may affect one clade or many, and be rapid or gradual; where they are rapid, and driven by a single lineage's adaptation to their environment,...
rather synchronously between 3 and 4 mya.
Notably, the divergence between the northern clades seems to have occurred far too early for the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
ice age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...
s to have played a major part. Rather, it appears that the "Common Bush-tanager" evolve
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
d in and was always confined to montane cloud forest. Given its sedentary habits, the phylogeny seems to be a result of a combination of habitat expanding and constricting due to Pliocene climate
Pliocene climate
During the Pliocene epoch climate became cooler and drier, and seasonal, similar to modern climates.The global average temperature in the mid-Pliocene was 2–3°C higher than today, global sea level 25m higher and Northern hemisphere ice sheet ephemeral before the onset of extensive glaciation...
changes and, less frequently, accidental dispersal (such as to the Sierra de los Tuxtlas and, earlier, to Mesoamerica in general).
The 5 northern clades are:
- Brown-headed Bush-tanager, Chlorospingus (ophthalmicus) ophthalmicus (Du Bus de Gisignies, 1847)
- Sierra Madre OrientalSierra Madre OrientalThe Sierra Madre Oriental is a mountain range in northeastern Mexico.-Setting:Spanning the Sierra Madre Oriental runs from Coahuila south through Nuevo León, southwest Tamaulipas, San Luis Potosí, Querétaro, and Hidalgo to northern Puebla, where it joins with the east-west running Eje Volcánico...
, from south-east San Luis PotosíSan Luis PotosíSan Luis Potosí officially Estado Libre y Soberano de San Luis Potosí is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 58 municipalities and its capital city is San Luis Potosí....
south to northern OaxacaOaxacaOaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions...
. May contain several subspeciesSubspeciesSubspecies 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...
. Status of birds from around Montserrate (westernmost ChiapasChiapasChiapas officially Estado Libre y Soberano de Chiapas is one of the 31 states that, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 118 municipalities and its capital city is Tuxtla Gutierrez. Other important cites in Chiapas include San Cristóbal de las...
) unknown, but these are probably dwighti. - Crown olive. Throat whitish-grey, speckled and with indistinct "whiskers". Breast-band yellow to chartreuse yellow. Ear region dark. Eyestreak thin. Thin, incomplete white spectacles. Forehead spots indistinct.
- Dusky-headed Bush-tanager, Chlorospingus (ophthalmicus) postocularis CabanisJean CabanisJean Louis Cabanis was a German ornithologist.Cabanis was born in Berlin. He studied at the University of Berlin from 1835 to 1839, and then travelled to North America, returning in 1841 with a large natural history collection. He was assistant and later director of the Berlin University Museum,...
, 1866
- Dusky-headed Bush-tanager, Chlorospingus (ophthalmicus) postocularis Cabanis
- Extreme SE Sierra Madre de ChiapasSierra Madre de ChiapasSierra Madre is a mountain range which runs northwest-southeast from the state of Chiapas in Mexico across Guatemala and into El Salvador and Honduras. Most of the volcanoes of Guatemala are a part of this range.A narrow coastal plain lies south the range, between the Sierra Madre and the Pacific...
(Volcán TacanáVolcán TacanáThe Tacaná Volcano is the second highest peak in Central America at . It is located in the Tacaná municipality of the Guatemalan department of San Marcos, and in Cacahoatán Municipality and Unión Juárez Municipality in the Mexican state of Chiapas....
; probably west to El Triunfo) and southwards along the Pacific slope of the Central American mountains, probably to NicaraguaNicaraguaNicaragua 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...
. If considered a separate species, includes subspecies honduratius and schistaceiceps. - Crown sepiaSepia (color)Sepia is a dark brown-grey color, named after the rich brown pigment derived from the ink sac of the common cuttlefish Sepia.The word sepia is the Latinized form of the Greek σηπία, sēpía, cuttlefish.-Sepia in human culture:...
. Throat almost white, speckled, no "whiskers". Breast-band yellow. Ear region whitish. Eyestreak thin, broader behind eye but no spectacles. Forehead unspotted.- White-fronted Bush-tanager, Chlorospingus (ophthalmicus) albifrons SalvinOsbert SalvinOsbert Salvin FRS was an English naturalist, best known for co-authoring Biologia Centrali-Americana with Frederick DuCane Godman. This was a 52 volume encyclopedia on the natural history of Central America....
& GodmanFrederick DuCane GodmanFrederick DuCane Godman D.C.L., F.R.S., F.L.S., F.G.S., F.R.G.S., F.E.S., F.Z.S., M.R.I., F.R.H.S., M.B.O.U. was an English lepidopterist, entomologist and ornithologist....
, 1889
- White-fronted Bush-tanager, Chlorospingus (ophthalmicus) albifrons Salvin
- Sierra Madre del SurSierra Madre del SurThe Sierra Madre del Sur is a mountain range in southern Mexico, extending from southern Michoacán east through Guerrero, to the Istmo de Tehuantepec in eastern Oaxaca.-Geography:...
in GuerreroGuerreroGuerrero officially Estado Libre y Soberano de Guerrero is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 81 municipalities and its capital city is Chilpancingo....
and Oaxaca. May contain several subspecies such as persimilis of the Sierra de Miahuatlán. - Crown cinnamonCinnamon (disambiguation)-Spices:*Cinnamon, a spice regionally made from several different plants, usually Cinnamomum verum and C. aromaticum*Cinnamomum, a genus of plants, from some of which cinnamon is produced, including:...
. Throat light buff with conspicuous "whiskers" and speckled sides. Breast-band tangerine yellow. Ear region dark. Eyestreak thin, merging into incomplete white spectacles and hence shaped like a horizontal teardropTearsTears are secretions that clean and lubricate the eyes. Lacrimation or lachrymation is the production or shedding of tears....
. Forehead with round white spots.- Dwight's Bush-tanager, Chlorospingus (ophthalmicus) dwighti Underdown, 1931
- Mountains of N Chiapas and easternmost Oaxaca, west to the Atlantic slope of GuatemalaGuatemalaGuatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...
and probably the western Sierra Madre de Chiapas. - Crown olive. Throat almost white, speckled and with indistinct "whiskers". Breast-band chartreuse yellow shading to olive green. Ear region dark. Eyestreak thick. Conspicuous incomplete white spectacles. Forehead spots indistinct.
- Wetmore's Bush-tanager, Chlorospingus (ophthalmicus) wetmorei Lowery & Newman, 1949
- Sierra de los TuxtlasSierra de los TuxtlasThe Sierra de Los Tuxtlas are a volcanic belt and mountain range along the southeastern Veracruz Gulf coast in southcentral Mexico....
, VeracruzVeracruzVeracruz, formally Veracruz de Ignacio de la Llave officially Estado Libre y Soberano de Veracruz de Ignacio de la Llave , is one of the 31 states that, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is... - Crown olive. Throat whitish-grey, speckled and with indistinct "whiskers". Breast-band yellow to chartreuse yellow. Ear region dark. Eyestreak thin. Thin but distinct incomplete white spectacles. White forehead spots V-shaped.
Chlorospingus ophthalmicus regionalis is found in Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
. Its relationship to the postocularis group and the Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
nian C. o. novicius warrants thorough study, as these three taxa appear to be rather intermediate between the main northern and the 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...
n groups, with whitish ears but a fairly brownish crown.
Southern group
Meanwhile, ecological data shows some interesting differences between southern populations too. Several subspecies appear to be well distinct, and there is much evidence suggesting they are distinct species. These birds are generally duskier and more indistinctly marked on the head than the northern populations.In the north of the Cordillera Oriental
Cordillera Oriental
Cordillera Oriental from the Spanish language meaning "Eastern range" may refer to:* Cordillera Oriental * Cordillera Oriental * Cordillera Oriental * Cordillera Oriental -See also:...
of 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...
, extending into the Cordillera de Mérida
Cordillera de Mérida
The Cordillera de Mérida is a series of mountain ranges, or massif, in northwestern Venezuela. The Cordillera de Mérida is a northeastern extension of the Andes Mountains. The ranges run southwest–northeast between the Venezuelan–Colombian border and the Venezuelan coastal range...
and 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...
of 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...
, a group of subspecies occurs that resembles the northernly birds; subspecies such as C. o. venezuelensis are included here. They might be most closely related to those around the Isthmus of Panama, or constitute a group distinct from the Central American forms. An undetermined and possibly new subspecies is found in Lara state in Venezuela, for example in Yacambú National Park. C. o. jacqueti occurs in Norte de Santander and possibly Boyacá
Boyacá Department
Boyacá is one of the 32 Departments of Colombia, and the remnant of one of the original nine states of the "United States of Colombia".Boyacá is centrally located within Colombia, almost entirely within the mountains of the Eastern Cordillera to the border with Venezuela, although the western end...
and Santander
Santander Department
Santander is a department of Colombia. Santander inherited the name of one of the nine original states of the United States of Colombia. It is located in the central northern part of the country, east of the Magdalena River, bordered to the south and southeast by Boyacá, to the northeast by Norte...
departments 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...
; it seems to be the most southernly representative of this group. These birds have a greyish-brown crown, a buffy-white speckled throat, and – like the birds further north – a white ear region. Their dawn song consists of a monotonous series of chit or chup notes.
Between Norte de Santander and the border region of Antioquia
Antioquia Department
Antioquia is one of the 32 departments of Colombia, located in the central northwestern part of Colombia with a narrow section that borders the Caribbean Sea. Most of its territory is mountainous with some valleys, much of which is part of the Andes mountain range...
, Boyacá, Cundinamarca
Cundinamarca Department
- Origin of the name :The name of Cundinamarca comes from Kundur marqa, an indigenous expression, probably derived from Quechua. Meaning "Condor's Nest", it was used in pre-Columbian times by the natives of the Magdalena Valley to refer to the nearby highlands....
and Santander departments, a complex situation exists, with C. o. eminens, C. o. exitelus and C. o. trudis being of unclear assignment as to subspecies group. If there is little intergradation in this region, the case for the southern Andean populations being a distinct species is rather robust. In fact, they have time and again been treated as a good species C. flavopectus.
The flavopectus group contains larger birds which lack a pronounced brown tinge on the crown; many members have this area purely grey to blackish. The white throat is almost devoid of spotting, and there is no white ear spot. This group includes taxa such as C. o. flavopectus and C. o. nigriceps from central to southern Colombia, C. o. phaeocephalus from Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
, C. o. peruvianus from Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
, or C. o. cinereocephalus and C. o. hiaticolus. Their dawn song consists of a series of chit notes, accelerating to higher-pitched chit-its and often accelerating further but descending in putch again to fade out in a churring trill trrrrrrrr.... Some, like C. o. phaeocephalus and C. o. nigriceps, have an even more complex dawn song, in which the middle part is replaced by a first trill at constant volume, breaking up into a few shorter trills trrrrrrrr tr tr tr... before ending with the fading lower trill. These populations also tend to give long series of chit calls between their songs.
In the far south of the species' range, C. o. argentatus is found in the yungas
Yungas
The Yungas is a stretch of forest along the eastern slope of the Andes Mountains from southeastern Peru through central Bolivia. It is a transitional zone between the Andean highlands and the eastern forests. Like the surrounding areas, it has characteristics of the Neotropic ecozone...
of northwestern 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...
. It is not known exactly how these birds relate to the taxa higher up in the Andes; they are generally little-studied. They have a tendency to build their nests uncharacteristically high up in trees; for this reason, it is unknown whether one-egg clutches are as commonly seen in this population as they seem to occur in the flavopectus group. It does not seem to like nesting less than 10 meters above the ground, but considering the high rate of failed nesting attempts (more than 35% abandoned nests in one study in El Rey National Park
El Rey National Park
The El Rey National Park is a national park of Argentina, located in the Anta Department, province of Salta, in the Argentine Northwest, 80 km from the provincial capital. It has an area of 441.62 km²....
), avoiding predators or other reasons for brood failure does not seem to be a very good explanation for this behavior.
Further reading
(2008). Phylogeography of a morphologically diverse Neotropical montane species, the Common Bush-Tanager (Chlorospingus ophthalmicus). Mol. Phyl. Evol.Molecular Phylogenetics and Evolution
Molecular Phylogenetics and Evolution is a peer-reviewed scientific journal of evolutionary biology and phylogenetics. The journal is edited by D.E. Wildman.-Indexing:The journal is indexed in:*EMBiology*Journal Citation Reports*Scopus*Web of Science...
47: 650–664