Delalande's Coua
Encyclopedia
Delalande's Coua also known as Snail-eating Coua and Delalande's Coucal, is an extinct 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 non-parasitic cuckoo
Cuckoo
The cuckoos are a family, Cuculidae, of near passerine birds. The order Cuculiformes, in addition to the cuckoos, also includes the turacos . Some zoologists and taxonomists have also included the unique Hoatzin in the Cuculiformes, but its taxonomy remains in dispute...

 from Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

. It only was known to science as an extant bird for a very short time in the early 19th century. There is some disagreement about its area of occurrence: Although there were claims that the bird was also found in the area of Fito and Maroantsetra
Maroantsetra
Maroantsetra is a market town and domestic seaport in Analanjirofo Region, Madagascar. It is located on the Bay of Antongil near .Maroantsetra is the main point of access to Masoala National Park and the Nosy Mangabe special reserve, and the headquarters of the park authority.Access to the town is...

 as well as near Toamasina
Toamasina
Toamasina , meaning "like salt" or "salty", unofficially and in French also Tamatave, is a city on the east coast of Madagascar on the Indian Ocean. The city is the chief seaport of the country, situated northeast of its capital and biggest city Antananarivo, near the centre of the eastern coast...

 (Tamatave), i.e., the coastal areas of northern Toamasina Province
Toamasina Province
Toamasina is a former province of Madagascar with an area of 71,911 km². It had a population of 2,855,600 . Its capital was Toamasina, the most important seaport of the country....

, all specimens with good locality data are from the offshore island of Nosy Boraha. As the vernacular name implies, land snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s were a favored food item of this species.

Extinction

Of the 14 specimens that exist nowadays, all but two are known to have taken between 1827 and 1834, many by the surgeon and naturalist Chevalier J A Bernier. The Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

 type
Biological type
In biology, a type is one particular specimen of an organism to which the scientific name of that organism is formally attached...

 specimen was in the collection of the Muséum national d'Histoire naturelle
Muséum national d'histoire naturelle
The Muséum national d'Histoire naturelle is the National Museum of Natural History in Paris, France.- History :The museum was formally founded on 10 June 1793, during the French Revolution...

 before that date, and one specimen may have been taken as late as 1850. As this species - the second-largest coua
Coua
Couas are large, mostly terrestrial birds of the cuckoo family, endemic to the island of Madagascar. Coua derives from koa, the Malagasy name for a cuckoo or coua, which is in turn an onomatopoeic of some species' call notes....

 extant in modern times - was very spectacular, it was much sought after as a museum piece. However, it probably was restricted to coastal rainforest on Nosy Boraha, and its habitat was largely destroyed by deforestation
Deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....

 in the course of the 19th century. Introduction of Black Rat
Black Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...

s may also have contributed to its demise, probably less by direct predation than by competition for food, but there probably was a thriving rat population on Nosy Boraha as soon as 1700, considering that the island was a favorite place for pirates to overhaul. Cats, which would have preyed on the bird, were probably introduced only in the 19th century and make a more likely candidate for an introduced species that had a negative impact on Delalande's Coua.

There are some reports that the locals on the adjacent mainland were still occasionally hunting this bird for its decorative plumage in the 1920s, but these seem in error, these records probably referring to the Blue Coua
Blue Coua
The Blue Coua is a species of cuckoo in the Cuculidae family.It is endemic to Madagascar.Its natural habitats are subtropical or tropical dry forests, subtropical or tropical moist lowland forests, subtropical or tropical mangrove forests, and subtropical or tropical moist montanes.The bird is a...

. What is known with certainty is that in 1932, large sums were offered to well-connected animal dealers in Antananarivo
Antananarivo
Antananarivo , formerly Tananarive , is the capital and largest city in Madagascar. It is also known by its French colonial shorthand form Tana....

 for specimens of Delalande's Coua, but they were unable to procure any. The color pattern of the species is unique among couas, which may be a hint that it evolved in fact in the isolation of Nosy Boraha and never occurred anywhere else. Specimens from "Tamatave" probably just indicate their port of shipment or the location of the animal dealer who procured them.

External links

  • 3D view of specimen RMNH 110.100 at Naturalis
    Naturalis
    Naturalis is the national natural history museum of the Netherlands, based in Leiden. It originated from the merger of the Rijksmuseum van Natuurlijke Historie and the Rijksmuseum van Geologie en Mineralogie in 1984. In 1986 it was decided that the museum had to become a public museum and a new...

    , Leiden (requires QuickTime
    QuickTime
    QuickTime is an extensible proprietary multimedia framework developed by Apple Inc., capable of handling various formats of digital video, picture, sound, panoramic images, and interactivity. The classic version of QuickTime is available for Windows XP and later, as well as Mac OS X Leopard and...

    browser plugin).
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