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Beach Thick-knee Esacus giganteus

Justification
This species qualifies as Near Threatened because it has a small population. If the population is found to be in decline it might qualify for uplisting to a higher threat category.

Taxonomic source(s)
Christidis, L.; Boles, W. E. 1994. The taxonomy and species of birds of Australia and its territories. Royal Australasian Ornithologists' Union, Melbourne.
Christidis, L.; Boles, W. E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Taxonomic note
The retention of the genus Esacus follows Andrew (1992) contra Sibley and Monroe (1990, 1993), because its merger with Burhinus does not do justice to the highly distinctive nature of Burhinus (=Esacus) giganteus and B. (=E.) recurvirostris, both of which have massive bills, strong black-and-white facial markings, and simplified dorsal patterning, all three of these characters being absent in other burhinids.

Synonym(s)
Burhinus giganteus Sibley and Monroe (1990, 1993), Burhinus giganteus giganteus Sibley and Monroe (1990, 1993), Esacus magnirostris BirdLife International (2004), Esacus magnirostris BirdLife International (2000), Esacus magnirostris Christidis and Boles (2008), Esacus magnirostris , Esacus magnirostris magnirostris Christidis and Boles (2008), Esacus neglectus neglectus Christidis and Boles (1994)

Distribution and population
Esacus giganteus is widespread around coasts from the Andaman Islands, India, Mergui Archipelago, Myanmar, islands off peninsular Thailand, and Peninsular Malaysia through Indonesia, Brunei, the Philippines, Papua New Guinea, the Solomon Islands, Vanuatu, New Caledonia (to France) and Australia. Its population in Australia may number c.5,000 birds and is probably stable (Garnett and Crowley 2000). Its density in Australia may have decreased locally on islands and in areas of the mainland where there are high levels of human disturbance and coastal development, especially around inhabited islands of the Great Barrier Reef and Torres Strait, and the wet tropical coast (A. Freeman in litt. 2007). Despite this, between the 1920s and 1970s the eastern part of the species's range appears to have extended south into New South Wales (Garnett and Crowley 2000). It is very rare on and around Sumatra, Vanuatu and New Caledonia, where it has not been seen for six years (N. Barre in litt. 2003).

Population justification
The population is thought to number c.5,000 individuals in Australia, 1,000 individuals in the Melanesian islands (G. Dutson in litt. 2002), and 10-20 individuals in New Caledonia. This totals at least 6,000 individuals, roughly equivalent to 4,000 mature individuals.

Trend justification
The population is suspected to be in decline owing to human disturbance and predation by invasive mammals.

Ecology
Pairs may be found on most beaches within its range; in Australia these include short stretches of muddy sand among mangroves, coralline sands on atolls and prime surf beaches (Garnett and Crowley 2000). Beaches associated with estuaries and mangroves are particularly favoured. Adults are sedentary, although the species has a tendency for wide-ranging vagrancy. It lays a single egg in a scrape in the sand at the landward edge of the beach, often using the same area repeatedly. It forages mainly in the intertidal zone on crustaceans and other invertebrates (Garnett and Crowley 2000).

Threats
The species appears to be threatened by extensive human disturbance of beach habitats in many areas (Garnett and Crowley 2000). It is also thought to be sensitive to predation by introduced mammals. Much of the species's habitat in Australia, particularly on islands, is secure. This species occurs at low densities and occupies linear habitats, increasing the potential for local extinctions to become regional ones; however, its apparent range expansion southwards in eastern Australia suggests that such extinctions do not represent genetic barriers (Garnett and Crowley 2000).

Conservation Actions Underway
No targeted conservation actions are known for this species. Conservation Actions Proposed
Maintain a register of inhabited beaches. Monitor population trends, especially where human disturbance is prevalant. If necessary, control the use of beaches by humans and their dogs, particularly during breeding. Determine the relationship between human disturbance and breeding success.

References
Barré, N.; Dutson, G. 2000. Liste commentée des oiseaux de Nouvelle-Calédonie. Alauda 68: 1-48.

BirdLife International. 2001. Threatened birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, U.K.

Garnett, S. T.; Crowley, G. M. 2000. The action plan for Australian birds 2000. Environment Australia, Canberra.

Further web sources of information
Australian Govt - Action Plan for Australian Birds 2000 - Recovery Outline

Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).

Text account compilers
Pilgrim, J., Garnett, S., Benstead, P., Harding, M., Taylor, J.

Contributors
Barré, N., Freeman, A.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Esacus giganteus. Downloaded from http://www.birdlife.org on 23/07/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/07/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Beach thick-knee (Esacus giganteus) 0

Key facts
Current IUCN Red List category Near Threatened
Family Burhinidae (Thick-knees)
Species name author (Wagler, 1829)
Population size 4000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 2,210,000 km2
Country endemic? No
Links to further information
- Additional Information on this species