Scarlet ibis | |
---|---|
A scarlet ibis at L'Oceanogràfic | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Pelecaniformes |
Family: | Threskiornithidae |
Genus: | Eudocimus |
Species: | E. ruber |
Binomial name | |
Eudocimus ruber | |
Synonyms | |
|
The scarlet ibis, sometimes called red ibis (Eudocimus ruber), is a species of ibis in the bird family Threskiornithidae. It inhabits tropical South America and part of the Caribbean. In form, it resembles most of the other twenty-seven extant species of ibis, but its remarkably brilliant scarlet coloration makes it unmistakable. It is one of the two national birds of Trinidad and Tobago, and its Tupi–Guarani name, guará, is part of the name of several municipalities along the coast of Brazil. [3]
This medium-sized wader is a hardy, numerous, and prolific bird, and it has protected status around the world. Its IUCN status is Least Concern. The legitimacy of Eudocimus ruber as a biological classification, however, is in dispute. Traditional Linnaean taxonomy classifies it as a unique species, but some scientists have moved to reclassify it as a subspecies of a more general American ibis species, along with its close relative, the American white ibis (Eudocimus albus).
The species was first classified by Carl Linnaeus in 1758. Initially given the binomial nomenclature of Scolopax rubra [4] (the name incorporates the Latin adjective ruber, "red"), the species was later designated Guara rubra and ultimately Eudocimus ruber. [5]
Biologically the scarlet ibis is very closely related to the American white ibis (Eudocimus albus) and is sometimes considered conspecific with it, [4] [6] leaving modern science divided over their taxonomy. The two birds each have exactly the same bones, claws, beaks, feather arrangements and other features – their one marked difference lies in their pigmentation. [7] Traditional taxonomy has regarded the two as separate and distinct. [7]
Early ornithological field research revealed no natural crossbreeding among the red and white, lending support to the two-species viewpoint. [7] More recent observation, however, has documented significant crossbreeding and hybridization in the wild. Researchers Cristina Ramo and Benjamin Busto found evidence of interbreeding in a population where the ranges of the scarlet and white ibises overlap along the coast and in the Llanos in Colombia and Venezuela. They observed individuals of the two species mating and pairing, as well as hybrid ibises with pale orange plumage, or white plumage with occasional orange feathers, and have proposed that these birds be classified as a single species. [4] Hybridization has been known to occur frequently in captivity. However, the two color forms persist in the wild despite overlapping ranges and hybrid offspring having a distinctive color type, so according to the cohesion species concept they would be functionally different species. [8]
Some biologists now wish to pair them with Eudocimus albus as two subspecies of the same American ibis. [4] Others simply define both of them as one and the same species, with ruber being a color variation of albus. [9]
Adult plumage is virtually all scarlet. The feathers may show various tints and shades, but only the tips of their wings deviate from their namesake color. A small but reliable marking, these wingtips are a rich inky black (or occasionally dark blue) and are found only on the longest primaries [10] – otherwise the birds' coloration is "a vivid orange-red, almost luminous in quality." [11] Scarlet ibises have red bills and feet however the bill is sometimes blackish, especially toward the end. [12] They have a long, narrow, decurved bill. Their legs and neck are long and extended in flight. [13]
A juvenile scarlet ibis is a mix of grey, brown, and white. As it grows, a heavy diet of red crustaceans produces the scarlet coloration. [14] The color change begins with the juvenile's second moult, around the time it begins to fly: the change starts on the back and spreads gradually across the body while increasing in intensity over a period of about two years. [10] The scarlet ibis is the only shorebird with red coloration in the world.
Adults are 55–63 centimetres (22–25 in) long, [15] and the males, slightly larger than females, typically weigh about 1.4 kilograms (3.1 lb). [10] Their bills are also on average around 22% longer than those of females. [16] The life span of the scarlet ibis is approximately sixteen years in the wild and twenty years in captivity. [17] An adult scarlet ibis has a wingspan of around 54 centimetres (21 in). [10] Though it spends most of its time on foot or wading through water, the bird is a very strong flyer: [14] they are highly migratory and easily capable of long-distance flight. They move as flocks in a classic V formation. [10]
The range of the scarlet ibis is very large, and colonies are found throughout vast areas of South America and the Caribbean islands. Native flocks exist in Brazil; Colombia; French Guiana; Guyana; Suriname; and Venezuela, as well as the islands of the Netherlands Antilles, and Trinidad and Tobago. [1] Flocks gather in wetlands and other marshy habitats, including mud flats, shoreline and rainforest. [10] Outlying colonies have been identified in the coastal areas of the states of Espírito Santo, Rio de Janeiro, São Paulo (for example in the Santos-Cubatão mangroves of the Baixada Santista district), Paraná and Santa Catarina. [18] In recent years, bird colonies can be seen as far south as in the coastal areas of Joinville and the island of São Francisco do Sul. [19] [20]
The highest concentrations are found in the Llanos region of western Venezuela and eastern Colombia. The fertile and remote tropical grassland plain of the Llanos provides a safe haven far from human encroachment. [11] Together with its relative the bare-faced ibis, the scarlet ibis is remarkably prolific and conspicuous in the region. [21]
Scarlet ibis vagrants have been identified in Belize, Ecuador, and Panama; Aruba, Cuba, Dominica, Grenada, and Jamaica; sightings have even been made in the United States. [1] The species may well have been a natural vagrant to the Gulf Coast in the 19th century or earlier – in The Birds of America , John James Audubon made brief remarks regarding three rubra specimens he encountered in Louisiana. [22] However, virtually all modern occurrences of the species in North America have been introduced or escaped birds. In one notable example from 1962, scarlet ibis eggs were placed in white ibis nests in Florida's Greynolds Park, and the resulting population hybridised easily, producing "pink ibises" that are still occasionally seen. [15] [23]
Mating pairs build nests in a simple style, typically "loose platforms of sticks" [14] of a quality described as "artless". [24] They roost in leaf canopies, mostly preferring the convenient shelter of young waterside mangrove trees. [25] Scarlet ibises like wet, muddy areas such as swamps, but for safety they build their nests in trees well above the water. If they can, they nest on islands, where their eggs and chicks are less likely to be in danger from predators. [26]
To attract a female, the male will perform a variety of mating rituals such as "preening, shaking, bill popping, head rubbing, and high flights. As with most birds, mating does not involve any coupling or insertion: instead, a transfer of seminal fluids occurs during external contact between the cloacal openings. [27] After a gestation period of five to six days, [10] the female lays a clutch of three to five smooth, matte eggs which typically incubate for 19–23 days. [17] [28] After a successful courtship, pairs remain faithful and cohabitant, sharing parental responsibilities for the young. [10]
In southeastern Brazil, the ibises gather in colonies in mid-September and build nests at the beginning of November. Egg laying within the colony was synchronous, with female birds laying eggs in three waves in early November, late December and late January. [18]
Their distinctive long, thin bills are used to probe for food in soft mud or under plants. [11] Popularly imagined to be eating only shrimp, a recent study in the Llanos has found that much of their diet consists of insects, of which the majority were scarabs and ground beetles. [29] One species in particular, a scarab beetle Dyscinetus dubius , formed a large part of the diet. [29] Other insect prey include water beetles and water bugs. [10] In contrast, the diet of the co-occurring American white ibis there differed, the latter consuming more bugs, fish and crustaceans. [29]
They do, however, eat much shrimp and other similar fare like ragworms ( Nereis ), mollusks (such as Melampus ), small crabs ( Aratus , Uca and Ucides ) and other crustaceans, such as crayfish. [10] [14] [17] [31] The large quantity of shrimp and other red shellfish produces a surfeit of astaxanthin, a carotenoid which is the key component of the birds' red pigmentation. [14] [32] Frogs, small snakes, small fish (Cichlidae), fruits and seeds are also occasional prey items for scarlet ibises. [10] [17] [33] When kept in zoos, the birds' diet often contains beetroot and carrot supplement to maintain color vibrancy in their plumage. [14]
The Llanos are notable in that these wetland plains support seven species of ibis in the one region. Here, scarlet ibis are the most aggressive, and attack other species to steal their food. They have also been observed trailing white-faced whistling ducks (Dendrocygna viduata) and domestic livestock, and catching insects disturbed by them. [34]
The scarlet ibis is a sociable and gregarious bird, and very communally-minded regarding the search for food and the protection of the young. They live in flocks of thirty or more. Members stay close, and mating pairs arrange their nests in proximity to other pairs in the same tree. [10]
For protection, flocks often congregate in large colonies of several thousand individuals. [10] They also regularly participate in mixed flocks, gaining additional safety through numbers: storks, spoonbills, egrets, herons and ducks are all common companions during feedings and flights. [10]
The species has protected status throughout the world, [14] and the International Union for Conservation of Nature has classified the scarlet ibis as a species of Least Concern on the IUCN Red List. [1] Though several local populations appear to be in decline, global totals remain relatively large and the current rate of losses is not considered a threat to the species' survival. [1] Nonetheless, recent losses by established populations in French Guiana have become a concern for conservationists, and in Brazil the bird has been included on a national list of endangered species. [35]
The scarlet ibis and the rufous-vented chachalaca, popularly known as the cocrico, are the national birds of Trinidad and Tobago respectively. [36] Both birds are featured on the coat of arms of Trinidad and Tobago. [36] [37] The cocrico is found on Tobago, Venezuela and Colombia. [36] The scarlet ibis is associated with Trinidad; there are not documented records of the scarlet ibis on Tobago for the last fifteen years. [38]
An important local habitat for the scarlet ibis is the wildlife sanctuary of Caroni Swamp of Trinidad, a 199 hectares (490 acres) wetland reserve first designated in 1953 specifically to provide a habitat for the scarlet ibis. [39]
Using the bird as a literary symbol, American author James Hurst composed a popular short story, "The Scarlet Ibis" (1960). [11] A more recent short story, "Scarlet Ibis" by Margaret Atwood, is included in Bluebeard's Egg (1983). [40] The name also belongs to a book of verse by American poet Susan Hahn. [41]
The family Threskiornithidae includes 36 species of large wading birds. The family has been traditionally classified into two subfamilies, the ibises and the spoonbills; however recent genetic studies have cast doubt on this arrangement, and have found the spoonbills to be nested within the Old World ibises, and the New World ibises as an early offshoot.
The American white ibis is a species of bird in the ibis family, Threskiornithidae. It is found from the southern half of the US East Coast, along the Gulf Coast states and south through most of the Caribbean coastal regions of Central America. This particular ibis species is a medium-sized wading bird, possessing an overall white plumage with black wing-tips, and having the typical downward-curving bill of the ibises, though of a bright red-orange color, the same hue as its long legs. Males are larger and have longer bills than females. The breeding range runs along the Gulf and Atlantic Coast, and the coasts of Mexico and Central America. Outside the breeding period, the range extends further inland in North America and also includes the Caribbean. It is also found along the northwestern South American coastline in Colombia and Venezuela. Populations in central Venezuela overlap and interbreed with the scarlet ibis. The two have been classified by some authorities as a single species.
The Australian white ibis is a wading bird of the ibis family, Threskiornithidae. It is widespread across much of Australia. It has a predominantly white plumage with a bare, black head, long downcurved bill, and black legs. While it is closely related to the African sacred ibis, the Australian white ibis is a native Australian bird. Contrary to urban myth, it is not a feral species introduced to Australia by people, and it does not come from Egypt.
The rufous-vented chachalaca is a member of an ancient group of birds of the family Cracidae, which are related to the Australasian mound builders. It inhabits northeast Colombia and northern Venezuela where it is called guacharaca, and the island of Tobago in Trinidad and Tobago where it is known as the cocrico and is one of the country's two national birds. It is also found on Bequia and Union Island in the Grenadines where it may have been introduced.
The bearded bellbird, also known as the campanero or anvil-bird, is a passerine bird which occurs in northern South America. The male is about 28 cm (11 in) long with white plumage apart from a brown head and black wings. At his throat hang several black, unfeathered wattles. The female is a little smaller with olive-green head and upper parts, yellow underparts streaked with green and a yellow vent area. The male has a loud, repeated metallic hammering call, as well as various other vocalisations.
The yellow oriole is a passerine bird in the family Icteridae. It should not be confused with the green oriole, sometimes alternatively called the Australasian yellow oriole, which is an Old World oriole.
The collared trogon is a near passerine bird in family Trogonidae, the quetzals and trogons. It is found in Mexico, throughout Central America, and in northern South America.
The Caroni Swamp is the largest mangrove wetland in Trinidad and Tobago. It is located on the west coast of Trinidad, south of Port of Spain and northwest of Chaguanas, where the Caroni River meets the Gulf of Paria.
The tropical parula is a small New World warbler. It breeds from southernmost Texas and northwest Mexico (Sonora) south through Central America to northern Argentina, including Trinidad and Tobago. This widespread and common species is not considered threatened by the IUCN.
The red siskin is a small endangered finch.
The ochre-lored flatbill or yellow-breasted flycatcher, is a passerine bird in the tyrant flycatcher family. It is found in South America, ranging from Colombia and Venezuela south to Peru, Bolivia, and Brazil, and on both Trinidad and Tobago. There are significant variations in its voice and plumage, with western birds duller and more olive, and eastern and northern birds brighter and more ochre-yellow. The two are sometimes considered separate species, the western olive-faced flatbill, T. viridiceps, and the eastern and northern ochre-lored flatbill, T. flaviventris.
The ruddy ground dove is a small New World tropical dove. It is a resident breeder from Mexico south to Brazil, Peru and Paraguay, and northern Argentina, and on Trinidad and Tobago. Individual birds can sometimes be seen in the southwestern USA, from southern Texas to southernmost California, primarily during winter.
The eared dove is a New World dove. It is a resident breeder throughout South America from Colombia to southern Argentina and Chile, and on the offshore islands from the Grenadines southwards. It may be a relatively recent colonist of Tobago and Trinidad. It appears to be partially migratory, its movements driven by food supplies.
The pale-vented pigeon is a large pigeon found in the tropical Americas. Formerly often placed in Columba, it actually belongs to a clade of the older New World genus Patagioenas. With its relatives it represents an evolutionary radiation extending through most of the warm-temperate to tropical Americas. Grey-hued birds, even their males generally lack iridescent display plumage, although the present species has some coppery gloss on the nape.
The collared plover is a small shorebird in the plover family, Charadriidae. It lives along coasts and riverbanks of the tropical to temperate Americas, from central Mexico south to Chile and Argentina.
Eudocimus is a genus of ibises, wading birds of the family Threskiornithidae. They occur in the warmer parts of the New World with representatives from the southern United States south through Central America, the West Indies, and South America.
The white-collared swift is a species of bird in the subfamily Cypseloidinae of the swift family Apodidae. It is found in Mexico, the Greater and Lesser Antilles, Trinidad, and every mainland South American country except Chile.
The maguari stork is a large species of stork that inhabits seasonal wetlands over much of South America, and is very similar in appearance to the white stork; albeit slightly larger. It is the only species of its genus to occur in the New World and is one of the only three New World stork species, together with the wood stork and the jabiru.
The sharp-tailed ibis is a species of ibis native to open wet savannas in parts of northern South America.
The scarlet ibis builds its artless nest of brush in inaccessible places on low trees.