The Christmas goshawk (''Tachyspiza fasciata natalis'') or Christmas Island goshawk is a

bird of prey Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...

in the goshawk and sparrowhawk

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Accipitridae The Accipitridae () is one of the four families within the order Accipitriformes, and is a family of small to large birds of prey with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects ...

. It is a

threatened A threatened species is any species (including animals, plants and fungi) which is vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensatio ...

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 ...

Christmas Island Christmas Island, officially the Territory of Christmas Island, is an States and territories of Australia#External territories, Australian external territory in the Indian Ocean comprising the island of the same name. It is about south o ...

, an

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

n territory in the eastern

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

Taxonomy

The taxon was described in 1889 by Lister as a full species, ''Accipiter natalis''. Since then there has been debate as to whether its affinities lie with the

brown goshawk The brown goshawk (''Tachyspiza fasciata'') is a medium-sized bird of prey in the family Accipitridae found in Australia and surrounding islands. This species was formerly placed in the genus ''Accipiter''. Taxonomy The brown goshawk was form ...

or the

grey goshawk The grey goshawk (''Tachyspiza novaehollandiae'') is a strongly built, medium-sized bird of prey in the family ''Accipitridae'' that is found in eastern and northern Australia. The white polymorphism (biology), morph of this species is known as ...

(''A. novaehollandiae''). In the 2004 national recovery plan for the taxon it is treated as a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of the brown goshawk, though the possibility has been raised of elevating it to the species level again.Hill (2004). Christidis and Boles (2008) treat it as a subspecies of the

variable goshawk The variable goshawk (''Tachyspiza hiogaster'') is a bird of prey native to Indonesia, Papua New Guinea and the Solomon Islands. It was recently elevated to species status, and was previously lumped together with the grey goshawk. This species wa ...

(''A. hiogaster''). Here it is treated as a subspecies of the brown goshawk pending further study of its genome.

Description

The Christmas goshawk is smaller and has more rounded wings than the nominate subspecies. Colouration is broadly similar, differing in that the hindneck, cap and ear coverts are dark grey, lacking a brown tinge. Females are distinctly larger than males.

Distribution and habitat

The goshawk is restricted to the 135 km² Christmas Island where it is found in the tropical

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

that covers 75% of the island, as well as in other habitats there such as regrowth forest and the edges of clearings.

Behaviour

Feeding

The goshawk feeds on a wide range of vertebrates and invertebrates, including birds, mammals, reptiles and insects. It takes its prey from the ground or in flight. It will hunt from a perch or chase birds through the forest. It is known to hunt native birds such as

emerald dove The emerald dove or common emerald dove (''Chalcophaps indica''), also called Asian emerald dove and grey-capped emerald dove, is a widespread resident breeding Columbidae, pigeon native to the tropical and subtropical parts of the Indian Subcon ...

, island thrush and Christmas Island white eye, as well as introduced birds including

red junglefowl The red junglefowl (''Gallus gallus''), also known as the Indian red junglefowl (and formerly the bankiva or bankiva-fowl), is a species A species () is often defined as the largest group of organisms in which any two individuals of the a ...

and

Java sparrow The Java sparrow (''Padda oryzivora''; Japanese: 文鳥, ''bunchō''), also known as the Java finch, Java rice sparrow or Java rice bird, is a small passerine bird. This estrildid finch is a resident breeding bird in Java, Bali and Bawean in In ...

Enemies and Competitors

There is a known instance of a Christmas goshawk preying upon a 5–6 week old

Abbott's booby Abbott's booby (''Papasula abbotti'') is an endangered seabird of the Sulidae, sulid family, which includes gannets and Booby, boobies. It is a large booby and is placed within its own monotypic genus. It was first identified from a specimen col ...

chick on 5 September 2005, in which an adult female goshawk knocked the booby chick off its nest and caused it to fall to its death. The

raptor Raptor(s) or RAPTOR may refer to: Animals The word "raptor" refers to several groups of avian and non-avian dinosaurs which primarily capture and subdue/kill prey with their talons. * Raptor (bird) or bird of prey, a bird that primarily hunt ...

attempted to drag its prey away but as the chick was heavier than the goshawk, she could only drag her prey about a meter away. About 20 minutes afterwards a

robber crab The coconut crab (''Birgus latro'') is a terrestrial species of giant hermit crab, and is also known as the robber crab or palm thief. It is the largest terrestrial arthropod known, with a weight up to . The distance from the tip of one leg to ...

was seen approaching the goshawk and dead chick, and after a tug-of-war lasting approximately 8 minutes the raptor retreated, allowing the

to successfully steal the carcass and escape with it into a hole under a log.

Status and conservation

The goshawk is listed as endangered under the

Environment Protection and Biodiversity Conservation Act 1999 The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cult ...

. There are no detailed population statistics for the goshawks, though the population is small and it has been estimated that there are no more than 100 mature birds, or 50 breeding pairs, on the island. The principal threat comes from

yellow crazy ant The yellow crazy ant (''Anoplolepis gracilipes''), also known as the long-legged ant or Maldive ant, is a species of ant, thought to be native to West Africa or Asia. They have been accidentally introduced to numerous places in the world's trop ...

s which were accidentally introduced to the island. The threat is not only that of ant predation of goshawk nestlings, but also indirectly from potentially massive changes to the ecology of the island caused by the ants.Garnett & Crowley, pp.190 and 652.

Notes

References

* Christidis, Les; & Boles, Walter E. (2008). ''Systematics and taxonomy of Australian birds''. CSIRO Publishing: Melbourne. * Garnett, Stephen T.; & Crowley, Gabriel M. (2000). ''The Action Plan for Australian Birds 2000''. Environment Australia: Canberra.

* Hill, Richard. (2004). National recovery plan for the Christmas Island Goshawk ''Accipiter fasciatus natalis''. Dept of the Environment and Heritage: Canberra.

* Marchant, S.; Higgins, P.J.; & Davies, J.N. (eds). (1994). ''Handbook of Australian, New Zealand and Antarctic Birds. Volume 2: Raptors to Lapwings''. Oxford University Press: Melbourne.

External links

* https://web.archive.org/web/20110605232431/http://abc.com.au/nature/island/ep2/locals/1e.htm {{Taxonbar, from=Q5111365 Tachyspiza, Christmas goshawk Birds of Christmas Island Endangered fauna of Oceania Christmas goshawk