Inaccessible Island Rail
Encyclopedia
The Inaccessible Island Rail (Atlantisia rogersi) is a small bird
of the rail family
, Rallidae
. It is the only species in its genus
. It is found only on Inaccessible Island
in the Tristan Archipelago
, and is notable for being the smallest extant flightless bird
in the world. Unlike many other islands, Inaccessible Island has remained free from introduced predators, allowing this species to flourish while many other flightless birds, including the even smaller Stephens Island Wren
, have perished.
The rail has an average weight of 30 g and a length of 17 cm. It is dark rusty-brown above and dark grey below, with a short black bill
and a red eye.
This rail is found throughout Inaccessible Island, but prefers grassland and open fern-bush. Its diet includes earthworm
s, moth
s, berries
, and seed
s.
A clutch of two egg
s is laid between October and January; chicks are vulnerable to predation by the Tristan Thrush
.
The Ascension Crake (Mundia elpenor) which disappeared some time before 1700 but was briefly mentioned and described by traveller and hobby naturalist Peter Mundy
in 1656 and Aphanocrex podarces, the Saint Helena Swamphen which disappeared before 1600 and has never been encountered by scientists were once considered congeners of A. rogersi. As they are considered to have evolved independently (with A. podarces probably not even being closely related), they have each been moved to a separate genus. Both species became extinct due to predation
by introduced species
, mainly cat
s and rat
s.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
of the rail family
Family
In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...
, Rallidae
Rallidae
The rails, or Rallidae, are a large cosmopolitan family of small to medium-sized birds. The family exhibits considerable diversity and the family also includes the crakes, coots, and gallinules...
. It is the only species in its genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
. It is found only on Inaccessible Island
Inaccessible Island
Inaccessible Island is an extinct volcano, 14 km² in area, rising out of the South Atlantic Ocean 45 km southwest of Tristan da Cunha. Inaccessible Island is located at . It is part of the archipelago of Tristan da Cunha, which is part of the overseas territory of the United Kingdom,...
in the Tristan Archipelago
Tristan da Cunha
Tristan da Cunha is a remote volcanic group of islands in the south Atlantic Ocean and the main island of that group. It is the most remote inhabited archipelago in the world, lying from the nearest land, South Africa, and from South America...
, and is notable for being the smallest extant flightless bird
Flightless bird
Flightless birds are birds which lack the ability to fly, relying instead on their ability to run or swim. They are thought to have evolved from flying ancestors. There are about forty species in existence today, the best known being the ostrich, emu, cassowary, rhea, kiwi, and penguin...
in the world. Unlike many other islands, Inaccessible Island has remained free from introduced predators, allowing this species to flourish while many other flightless birds, including the even smaller Stephens Island Wren
Stephens Island Wren
The Stephens Island Wren or Lyall's Wren was a nocturnal, flightless, insectivorous passerine.-Habitat:...
, have perished.
The rail has an average weight of 30 g and a length of 17 cm. It is dark rusty-brown above and dark grey below, with a short black bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
and a red eye.
This rail is found throughout Inaccessible Island, but prefers grassland and open fern-bush. Its diet includes earthworm
Earthworm
Earthworm is the common name for the largest members of Oligochaeta in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female...
s, moth
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
s, berries
Berry
The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....
, and seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s.
A clutch of two 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 is laid between October and January; chicks are vulnerable to predation by the Tristan Thrush
Tristan Thrush
The Tristan Thrush , also known as the Starchy, is a species of bird in the thrush family that is endemic to the isolated Tristan da Cunha archipelago in the South Atlantic Ocean.-Description:...
.
The Ascension Crake (Mundia elpenor) which disappeared some time before 1700 but was briefly mentioned and described by traveller and hobby naturalist Peter Mundy
Peter Mundy
-Life:He came from Penryn in Cornwall. In 1609 he accompanied his father to Rouen, and was then sent to Gascony to learn French. In May 1611 he went as a cabin-boy in a merchant ship, and gradually rose in life until he became of independent circumstances....
in 1656 and Aphanocrex podarces, the Saint Helena Swamphen which disappeared before 1600 and has never been encountered by scientists were once considered congeners of A. rogersi. As they are considered to have evolved independently (with A. podarces probably not even being closely related), they have each been moved to a separate genus. Both species became extinct due to predation
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...
by introduced species
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
, mainly cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s and rat
Rat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
s.