The Comoro blue pigeon (''Alectroenas sganzini'') is a species of

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

in the family

Columbidae Columbidae is a bird Family (biology), family consisting of doves and pigeons. It is the only family in the Order (biology), order Columbiformes. These are stout-bodied birds with small heads, relatively short necks and slender bills that in ...

. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the

Comoros The Comoros, officially the Union of the Comoros, is an archipelagic country made up of three islands in Southeastern Africa, located at the northern end of the Mozambique Channel in the Indian Ocean. Its capital and largest city is Moroni, ...

and the coralline

Seychelles Seychelles (, ; ), officially the Republic of Seychelles (; Seychellois Creole: ), is an island country and archipelagic state consisting of 155 islands (as per the Constitution) in the Indian Ocean. Its capital and largest city, Victoria, ...

. It is rated as a species of

near threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...

on the International Union for Conservation of Nature Red List of Endangered Species.

Description

The Comoro blue pigeon measures about in length. The male weighs from , and the female weighs about . It has a silvery gray head, neck, and upper breast. The neck feathers are silvery white in colour, and are very long and deeply partitioned. The

beak The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for pecking, grasping, and holding (in probing for food, eating, manipulating and ...

is greenish or yellowish grey, and has a pale yellow or greenish white tip. It has black lower

underparts Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

. The lower part of the breast is shiny violet-blue, and the belly and flanks are more greenish blue in colour.

Distribution and habitat

The Comoro blue pigeon is

to the

and the coralline

. Its natural

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

s are

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

moist lowland

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

s, subtropical or tropical mangrove forests, and subtropical or tropical moist

montane forest Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

s. It is found at elevations ranging from above sea level.

Behaviour

The Comoro blue pigeon is sometimes solitary, but may occur in groups of up to 15 individuals. These often fly about above the water between islands in the

Aldabra group The Aldabra Group are part of the Outer Islands of the Seychelles, lying in the southwest of the island nation, around from the capital, Victoria, on Mahé Island. Population and area The group contains four islands and atolls. By far the lar ...

, making regular journeys in one direction in the mornings and back again in the evenings. Their flight is fast, interspersed with wing claps. They have a habit of perching high in a tree in full sun and raising one wing to expose it to the sun. They are arboreal, fruit-eating birds which seem to avoid landing on the ground; however, small stones found in their crop seem to indicate that they do sometimes descend to the earth.

Status and conservation

As of 2017, the Comoro blue pigeon has been rated as a species of

on the

IUCN Red List of Endangered Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological spe ...

. This is because although it has a restricted distribution, its range size is considered to be more than 20,000 km² (7,700 mi²). Despite a decreasing or fluctuating range, the area of occurrence is above the criterion to warrant it a vulnerable rating. Although its population has not been determined, it is thought to be above 10,000. Also, even though its population is decreasing, the rate of decline is thought to be less than 30% over ten years or three generations and thus is below the vulnerable criteria. It is reportedly extinct in some areas, commonly found in others, and extinct on many small islands.

References

{{Taxonbar, from=Q1264261 Alectroenas Birds described in 1854 Taxa named by Charles Lucien Bonaparte Birds of Mayotte Birds of the Comoros Birds of Seychelles Taxonomy articles created by Polbot