Alaotra Grebe
Encyclopedia
The Alaotra Grebe also known as Delacour's Little Grebe or Rusty Grebe, was a grebe
endemic to Lake Alaotra
and surrounding lakes in Madagascar
. The last sighting (which may have been a hybrid with the Little Grebe
) was in 1985 and the species was declared extinct in 2010. Only one photograph of the species is known to exist.
The grebe was a bird of about 10 inches (25.4 cm) in length. Its ability to fly long distances is believed to have been restricted by its small wings.
The species declined in the course of the 20th century, mainly because of habitat destruction
, entanglement with monofilament gillnets and predation by the introduced snakehead murrel (Channa striata). Also, the few remaining birds increasingly hybridized with Little Grebes which use the wetlands as a migration
stopover site; as the species differed in several key aspects, the hybrid birds may have suffered from decreased fitness
, to the detriment of the rufolavatus gene pool
.
The Madagascar Pochard
, which also lived on Lake Alaotra, was thought to be extinct but was rediscovered in 2006. Unlike this species, however, the grebe had poor powers of dispersal and was never found elsewhere.
The species was officially declared extinct in 2010, 25 years after the last confirmed sighting. Although some species have been classified as extinct and later have been found to still exist, Leon Bennun, the director of the conservation organization BirdLife International
has stated that "no hope remains for this species" and blames the "unforeseen consequences" of human action.
This extinction brings the number of confirmed bird extinctions since 1600 AD to 162. The previous confirmed extinction of a bird species was of the Liverpool Pigeon
(Caloenas maculata) in 2008.
Grebe
A grebe is a member of the Podicipediformes order, a widely distributed order of freshwater diving birds, some of which visit the sea when migrating and in winter...
endemic to Lake Alaotra
Lake Alaotra
Lake Alaotra is the largest lake in Madagascar, located in Toamasina Province, in the northern central plateau. Its basin is composed of shallow freshwater lakes and marshes surrounded by areas of dense vegetation. It forms the center of the island's most important rice-growing region...
and surrounding lakes in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
. The last sighting (which may have been a hybrid with the Little Grebe
Little Grebe
The Little Grebe , also known as Dabchick, member of the grebe family of water birds. At 23 to 29 cm in length it is the smallest European member of its family. It is commonly found in open bodies of water across most of its range.-Description:The Little Grebe is a small water bird with a pointed...
) was in 1985 and the species was declared extinct in 2010. Only one photograph of the species is known to exist.
The grebe was a bird of about 10 inches (25.4 cm) in length. Its ability to fly long distances is believed to have been restricted by its small wings.
The species declined in the course of the 20th century, mainly because of habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
, entanglement with monofilament gillnets and predation by the introduced snakehead murrel (Channa striata). Also, the few remaining birds increasingly hybridized with Little Grebes which use the wetlands as a migration
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
stopover site; as the species differed in several key aspects, the hybrid birds may have suffered from decreased fitness
Fitness (biology)
Fitness is a central idea in evolutionary theory. It can be defined either with respect to a genotype or to a phenotype in a given environment...
, to the detriment of the rufolavatus gene pool
Gene pool
In population genetics, a gene pool is the complete set of unique alleles in a species or population.- Description :A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can survive bouts of intense selection...
.
The Madagascar Pochard
Madagascar Pochard
The Madagascar Pochard is an extremely rare diving duck of the genus Aythya, previously thought extinct. Prior to a rediscovery in 2006, the last confirmed sighting of the species was at Lake Alaotra on the Central Plateau of Madagascar in 1991...
, which also lived on Lake Alaotra, was thought to be extinct but was rediscovered in 2006. Unlike this species, however, the grebe had poor powers of dispersal and was never found elsewhere.
The species was officially declared extinct in 2010, 25 years after the last confirmed sighting. Although some species have been classified as extinct and later have been found to still exist, Leon Bennun, the director of the conservation organization BirdLife International
BirdLife International
BirdLife International is a global Partnership of conservation organisations that strives to conserve birds, their habitats and global biodiversity, working with people towards sustainability in the use of natural resources...
has stated that "no hope remains for this species" and blames the "unforeseen consequences" of human action.
This extinction brings the number of confirmed bird extinctions since 1600 AD to 162. The previous confirmed extinction of a bird species was of the Liverpool Pigeon
Liverpool Pigeon
The Liverpool Pigeon or Spotted Green Pigeon is a presumed extinct pigeon species from an unknown provenance.-Description:...
(Caloenas maculata) in 2008.
See also
- Atitlán GrebeAtitlán GrebeThe Atitlán Grebe , also known as Giant Grebe, Giant Pied-billed Grebe, or Poc, is an extinct water bird, a relative of the Pied-billed Grebe. It was endemic at the Lago de Atitlán in Guatemala at an altitude of 1700 m asl. Thanks to the field work of the American ecologist Anne LaBastille, its...
, extinct since 1989 for similar reasons - Endemic birds of Madagascar and western Indian Ocean islandsEndemic birds of Madagascar and western Indian Ocean islandsThis article is one of a series providing information about endemism among birds in the World's various zoogeographic zones. For an overview of this subject see Endemism in birds.- Patterns of endemism :...