Christmas Island Thrush
Encyclopedia
The Christmas Island Thrush (Turdus poliocephalus erythropleurus ), ia a subspecies of the Island Thrush
(Turdus poliocephalus). It is endemic to Christmas Island
, an Australia
n territory in the Indian Ocean
.
, where it was plentiful for many years on three islands of the main atoll as well as on North Keeling
. However, between the 1940s and 1980s it became extinct
there. It is commonly found in most habitats on Christmas Island, including rainforest
and garden
s. It is less common in Pandanus
thickets, dense regrowth and post-mining wasteland.
s, tree ferns and sometimes on the ledges of buildings. The clutch size is usually 2-3, the incubation period is 18 days, fledging in 17–19 days. Several broods may be raised in a season.
s, including insects, snails and earthworms, seeds and fallen fruit.
s. It is listed by the Australian Government as being Critically Endangered
.
Island Thrush
The Island Thrush is a common forest bird in the thrush family. Almost 50 subspecies have been described, ranging from Taiwan, through South East Asia and Melanesia, to Samoa, exhibiting great differences in plumage...
(Turdus poliocephalus). It is endemic to Christmas Island
Christmas Island
The Territory of Christmas Island is a territory of Australia in the Indian Ocean. It is located northwest of the Western Australian city of Perth, south of the Indonesian capital, Jakarta, and ENE of the Cocos Islands....
, an Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n territory in the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
.
Description
The Christmas Island Thrush has a mainly dark grey-brown head, paler grey-brown throat and upper breast, with olive-brown upperparts. The flanks, lower breast and sides of belly are orange, with a white belly and vent. It is about 21 cm in length, with a wingspan of 34 cm and a weight of 55 g. Its bill, orbital ring and legs are yellow-orange. Males and females are similar in size and appearance.Distribution and habitat
The subspecies is now limited to Christmas Island. Between 1885 and 1900 it was introduced to the Cocos (Keeling) IslandsCocos (Keeling) Islands
The Territory of the Cocos Islands, also called Cocos Islands and Keeling Islands, is a territory of Australia, located in the Indian Ocean, southwest of Christmas Island and approximately midway between Australia and Sri Lanka....
, where it was plentiful for many years on three islands of the main atoll as well as on North Keeling
North Keeling
North Keeling is a small, uninhabited coral atoll of about 1.2 km2, about 25 km north of Horsburgh Island. It is the northernmost atoll and island of the Australian territory of the Cocos Islands...
. However, between the 1940s and 1980s it became extinct
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
there. It is commonly found in most habitats on Christmas Island, including rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
and garden
Garden
A garden is a planned space, usually outdoors, set aside for the display, cultivation, and enjoyment of plants and other forms of nature. The garden can incorporate both natural and man-made materials. The most common form today is known as a residential garden, but the term garden has...
s. It is less common in Pandanus
Pandanus
Pandanus is a genus of monocots with about 600 known species. They are numerous palmlike dioecious trees and shrubs native of the Old World tropics and subtropics. They are classified in the order Pandanales, family Pandanaceae.-Overview:...
thickets, dense regrowth and post-mining wasteland.
Breeding
The thrush breeds mainly from early October until the middle of March, though there are records from other months. It nests in treeTree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s, tree ferns and sometimes on the ledges of buildings. The clutch size is usually 2-3, the incubation period is 18 days, fledging in 17–19 days. Several broods may be raised in a season.
Feeding
It forages mainly on the ground, in leaf litter in the forest and forest clearings, as well as on lawns, for small invertebrateInvertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s, including insects, snails and earthworms, seeds and fallen fruit.
Status and conservation
In 2000 the population of the Christmas Island Thrush was estimated to comprise some 4000 birds. The main threat to the subspecies, as well as to other Christmas Island endemic birds, is predation of its nestlings by introduced yellow crazy antYellow crazy ant
The yellow crazy ant is a species of ant, introduced accidentally to northern Australia and Christmas Island in the Indian Ocean, that has wreaked ecological damage in both locations....
s. It is listed by the Australian Government as being Critically Endangered
Critically Endangered
Critically Endangered is the highest risk category assigned by the IUCN Red List for wild species. Critically Endangered means that a species' numbers have decreased, or will decrease, by 80% within three generations....
.