South American Bittern
Encyclopedia
The Pinnated Bittern also known as the South American Bittern, is a large member of the heron
family
(Ardeidae) found in the New World
tropics
. Like the other Botaurus
bittern
s, its plumage
is mostly buffy-brown and cryptically patterned. Though it is a widespread species, it is rarely seen – presumably due to its skulking habits – and much about its life history remains little known.
Both adults and immatures are generally buffy, though heavily marked with cryptic patterning. Juveniles tend to have a somewhat more reddish ground color. The throat is unmarked white, the foreneck is white broadly streaked with pale brown, and the rest of the neck is buff with thin black barring. The breast and belly are white with broad pale brown streaks, while the back is buff, heavily streaked and barred with black. Rectrices are black in males and brown in females; the slate-grey remiges
create a conspicuous two-toned effect in flight.
The bill is stout and strong, yellowish overall with a dusky upper mandible. The bare facial skin is bright yellow, with a brown line running across the lores. The legs are greenish-yellow, and the iris is yellow.
. During the breeding season, the male booms at dusk and into the night; his call is a deep poonk or poonkoo.
Johann Georg Wagler
, who first described the Pinnated Bittern in 1829, placed it in the genus Ardea
at that time. It is sometimes included in a superspecies
with the American Bittern
(B. lentiginosus), while other authors consider the entire genus Botaurus to consist of a single superspecies.
There are currently two recognized subspecies
, which are separated by a gap in Central America
:
as much as 8,500 ft (2,600 m) ASL
.
It can be found in a variety of freshwater
habitats, including dense reedbeds and lake borders, flooded tall-grass pasture
s, marsh
es and overgrown ditches. Typically, the vegetation in its habitat is dominated by tall sedge
s (Cyperaceae), water hyacinth
(Eichornia), rush
es (Juncus), typical reeds
(Phragmites) or cattails (Typha). It will also utilize plantations of rice
(Oryza) and sugarcane
(Saccharum).
The Pinnated Bittern is largely nocturnal. Though generally solitary, it will gather in small loose groups at favored feeding areas. When frightened, it tends to freeze with its body crouched low and its head raised vertically just high enough to see. It typically flushes only at close range.
Estimates of its population, and of overall population trends, are unknown. Due to its wide range, it is nonetheless regarded a Species of Least Concern
by the IUCN.
(including eel
s), reptile
s, amphibian
s, arthropod
s and small mammal
s (even including young Common Marmoset
s, Callithrix jacchus), all of which are typically taken in ambush. The Pinnated Bittern is a patient hunter, often standing motionless for long periods while waiting for prey
to move within range.
, a platform or shallow cup of rush stems or other plant material, is typically built among thick vegetation not far above the water surface. The female lays two to three olive-brown egg
s, and is thought to do all of the incubation
. Pinnated Bitterns are almost exclusively wet season
breeders.
Heron
The herons are long-legged freshwater and coastal birds in the family Ardeidae. There are 64 recognised species in this family. Some are called "egrets" or "bitterns" instead of "heron"....
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...
(Ardeidae) found in the New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
tropics
Tropics
The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately N and the Tropic of Capricorn in the southern hemisphere at S; these latitudes correspond to the axial tilt of the Earth...
. Like the other Botaurus
Botaurus
Botaurus is a genus of bitterns, a group of wading bird in the heron family Ardeidae. It has a single representative species in each of North America, Central and South America, Eurasia and Australasia...
bittern
Bittern
Bitterns are a classification of birds in the heron family, Ardeidae, a family of wading birds. Species named bitterns tend to be the shorter-necked, often more secretive members of this family...
s, its 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...
is mostly buffy-brown and cryptically patterned. Though it is a widespread species, it is rarely seen – presumably due to its skulking habits – and much about its life history remains little known.
Description
The Pinnated Bittern is a large heron, measuring between 25–30 in (63.5–76 cm) with a weight of roughly 1.8 lb (800 g). Sexes are similarly plumaged, but females tend to be smaller than males and have brown instead of black on the tail.Both adults and immatures are generally buffy, though heavily marked with cryptic patterning. Juveniles tend to have a somewhat more reddish ground color. The throat is unmarked white, the foreneck is white broadly streaked with pale brown, and the rest of the neck is buff with thin black barring. The breast and belly are white with broad pale brown streaks, while the back is buff, heavily streaked and barred with black. Rectrices are black in males and brown in females; the slate-grey remiges
Flight feather
Flight feathers are the long, stiff, asymmetrically shaped, but symmetrically paired feathers on the wings or tail of a bird; those on the wings are called remiges while those on the tail are called rectrices . Their primary function is to aid in the generation of both thrust and lift, thereby...
create a conspicuous two-toned effect in flight.
The bill is stout and strong, yellowish overall with a dusky upper mandible. The bare facial skin is bright yellow, with a brown line running across the lores. The legs are greenish-yellow, and the iris is yellow.
Voice
If flushed, the Pinnated Bittern gives a rough rawk-rawk-rawk callBird song
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs are the bird sounds that are melodious to the human ear. In ornithology and birding, songs are distinguished by function from calls.-Definition:The distinction between songs and calls is based upon...
. During the breeding season, the male booms at dusk and into the night; his call is a deep poonk or poonkoo.
Taxonomy and systematics
German naturalistNatural history
Natural history is the scientific research of plants or animals, leaning more towards observational rather than experimental methods of study, and encompasses more research published in magazines than in academic journals. Grouped among the natural sciences, natural history is the systematic study...
Johann Georg Wagler
Johann Georg Wagler
Johann Georg Wagler was a German herpetologist.Wagler was assistant to Johann Baptist von Spix, and became Director of the Zoological Museum at the University of Munich after Spix's death in 1826...
, who first described the Pinnated Bittern in 1829, placed it in the genus Ardea
Ardea (genus)
Ardea is a genus of herons. Linnaeus named this genus as the Great Herons, referring to the generally large size of these birds, typically 80–100 cm or more in length....
at that time. It is sometimes included in 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...
with the American Bittern
American Bittern
The American Bittern is a wading bird of the heron family Ardeidae. New evidence has led the American Ornithologists' Union to move the heron family into the order Pelecaniformes .-Description:...
(B. lentiginosus), while other authors consider the entire genus Botaurus to consist of a single superspecies.
There are currently two recognized 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...
, which are separated by a gap in Central America
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...
:
- Botaurus pinnatus caribaeus Dickerman, 1961 – Eastern MexicoMexicoThe 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...
, BelizeBelizeBelize is a constitutional monarchy and the northernmost country in Central America. Belize has a diverse society, comprising many cultures and languages. Even though Kriol and Spanish are spoken among the population, Belize is the only country in Central America where English is the official...
and (rarely) 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...
.
- On average longer bill, shorter wings and tail, paler, less streaking on throat.
- Botaurus pinnatus pinnatus (Wagler, 1829) – southeastern Nicaragua to EcuadorEcuadorEcuador , 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...
and the Guianas, south through BrazilBrazilBrazil , 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...
to ParaguayParaguayParaguay , 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 northeastern ArgentinaArgentinaArgentina , 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...
.
- Botaurus pinnatus pinnatus (Wagler, 1829) – southeastern Nicaragua to Ecuador
- On average shorter bill, longer wings and tail, darker, more streaking on throat.
Distribution and ecology
The alternate name "South American Bittern" is a bit misleading, as the species is found as far north as southern Mexico. Its range stretches from the Atlantic slope of southeastern Mexico to northern Argentina, though there are few records for Guatemala and for Honduras. The species occurs mainly in low-lying regions, but has been recorded in the Cordillera Oriental of ColombiaColombia
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...
as much as 8,500 ft (2,600 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...
.
It can be found in a variety of freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
habitats, including dense reedbeds and lake borders, flooded tall-grass pasture
Pasture
Pasture is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep or swine. The vegetation of tended pasture, forage, consists mainly of grasses, with an interspersion of legumes and other forbs...
s, marsh
Marsh
In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....
es and overgrown ditches. Typically, the vegetation in its habitat is dominated by tall sedge
Cyperaceae
Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...
s (Cyperaceae), water hyacinth
Water hyacinth
The seven species of water hyacinth comprise the genus Eichhornia. Water hyacinth are a free-floating perennial aquatic plant native to tropical and sub-tropical South America. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as 1 meter in...
(Eichornia), rush
Juncus
Juncus is a genus in the plant family Juncaceae. It consists of some 200 to 300 or more species of grassy plants commonly called rushes...
es (Juncus), typical reeds
Phragmites
Phragmites, the Common reed, is a large perennial grass found in wetlands throughout temperate and tropical regions of the world. Phragmites australis is sometimes regarded as the sole species of the genus Phragmites, though some botanists divide Phragmites australis into three or four species...
(Phragmites) or cattails (Typha). It will also utilize plantations of rice
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...
(Oryza) and sugarcane
Sugarcane
Sugarcane refers to any of six to 37 species of tall perennial grasses of the genus Saccharum . Native to the warm temperate to tropical regions of South Asia, they have stout, jointed, fibrous stalks that are rich in sugar, and measure two to six metres tall...
(Saccharum).
The Pinnated Bittern is largely nocturnal. Though generally solitary, it will gather in small loose groups at favored feeding areas. When frightened, it tends to freeze with its body crouched low and its head raised vertically just high enough to see. It typically flushes only at close range.
Estimates of its population, and of overall population trends, are unknown. Due to its wide range, it is nonetheless regarded a Species of 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.
Food and feeding
Its diet is varied, consisting of fishFish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
(including eel
Eel
Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...
s), reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s, amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s, 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 and small 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 (even including young 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...
s, Callithrix jacchus), all of which are typically taken in ambush. The Pinnated Bittern is a patient hunter, often standing motionless for long periods while waiting for prey
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
to move within range.
Breeding
As typical for Botaurinae (but unlike most herons), the Pinnated Bittern is a solitary breeder. Its nestBird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
, a platform or shallow cup of rush stems or other plant material, is typically built among thick vegetation not far above the water surface. The female lays two to three olive-brown egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
s, and is thought to do all of the incubation
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
. Pinnated Bitterns are almost exclusively wet season
Wet season
The the wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region occurs. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the...
breeders.