Justification This species has a small population which breeds within a tiny Area of Occupancy on just one island, and which is continuing to decline. For these reasons it is listed as Critically Endangered.

Family/Sub-family Fregatidae

Species name author Mathews, 1914

Taxonomic source(s) Christidis and Boles (1994), Dowsett and Forbes-Watson (1993), Sibley and Monroe (1990, 1993)

Identification 90-100 cm. Huge, mostly black, fork-tailed seabird with white belly and pale bar on upperwings. Adult male has red gular pouch and small white belly patch; long, dark grey, hooked bill. Adult female has black head, throat and spur on sides of upper breast and white collar, breast, belly and spur onto axillaries. Pink bill and red orbital ring. Similar spp. Adult Great Frigatebird F. minor male has all black underparts. Female has dusky throat, black axillaries and lower belly. Adult Lesser Frigatebird F. ariel is smaller with black belly. Immature F. minor has shorter bill and tawny-white head (tawny-yellow in F. andrewsi). Immature F. ariel is smaller and tends to have dark belly. Juvenile F. andrewsi tends to have white lower belly and white spur on axillaries. See James (2004) for detailed notes on identifying frigatebirds.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

2,400 - 4,800

decreasing

3,610,000 km²

Yes

Range & population Fregata andrewsi is endemic as a breeding species to Christmas Island (to Australia). In 2003 it was estimated that there were 1,171 (± 58) breeding pairs. The number of nests was probably between 3% and 16% lower in 2003 than 1985 (one generation; 1985 estimates ranging from 1,320-1,620 pairs⁴), but this may not be an accurate indication of population trends. Due to biennial breeding, the total breeding population is between one and two times the number of pairs nesting per annum (i.e. 1,200-2,400 pairs). An historical review of the extent and decline of the four sub-colonies suggests that the pre-settlement population was about 6,300 breeding pairs per annum, but declined to 4,500 by 1910, 3,500 by 1945, 2,500 by 1967, and 1,500 by 1978. If this reconstruction is correct, then the population declined by about 66% over three generations between 1945 and 2003³. In 2003 there were four sub-colonies (since reduced to three) covering an area of c.49 ha^3,4. The Flying Fish Cove sub-colony probably contained c.50 ha of habitat in 1887; it underwent an almost complete decline in the early 1900s, and in 2003 it contained only c.10 ha of habitat and two nests. The Dryers sub-colony underwent an almost complete decline by the 1970s, and in 2003 contained c.62 ha of habitat and 20 nests. The Golf Course sub-colony lost c.13 ha (25%) in the 1940s, and in 2003 it contained c.25 ha of habitat and an estimated 828 (± 42) nests. The Cemetery sub-colony contained 46 ha of habitat and an estimated 321 (± 15) nests in 2003³. Surveys in 2004 showed a significant increase in number of nests, with 767 nests in 244 nest trees at the largest colony⁹ but surveys in 2005 showed a return to 2003 levels, suggesting that inter-annual variation rather than population growth explains the increase in numbers in 2004. Breeding and non-breeding birds have been recorded foraging at low densities in the Indo-Malay Archipelago⁷ over the Sunda Shelf to the South China Sea, the Andaman Sea, the Sulu Sea and the Gulf of Thailand^13,14, commuting directly over Java in the process⁶. When not breeding the species ranges widely across the seas of South-East Asia to Indochina and south to northern Australia⁴, but its status in the Indian Ocean to the west is less well known.

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: It nests in tall forest trees. Terminalia catappa and Celtis timorensis trees hold 65.5% of all nests^5. It is only capable of raising a maximum of one fledgling every two years. It forages for flying fish, squid and other marine creatures, and is largely dependent on subsurface predators to drive prey to the surface. Most food is captured by plucking it from the sea surface while on the wing, but it is also an accomplished aerial kleptoparasite. Evidence suggests that breeding birds frequently forage hundreds or even thousands of kilometres from the colony. Satellite tracking showed one female with a large chick undertook a non-stop 26-day 4,000 km return flight from Christmas Island via Sumatra and Borneo⁶. Replacement rate of pairs is thought to be extremely slow (15-25 years) rendering the population slow to recover following declines⁵.

Threats About a quarter of the breeding area was cleared before 1946 for phosphate mining, and the Flying Fish Cove colony was largely deserted because of continuing dust fallout from phosphate dryers. Future habitat loss is possible through clearance for mining. A new application to mine a 250 ha area of rainforest¹² is currently under review. About two thirds of the nests are now located in a single colony, making the species vulnerable to cyclones. Poaching ceased in the 1980s. A possible threat is the introduced yellow crazy ant Anoplolepis gracilipes which formed super-colonies during the 1990s and spread rapidly to cover about 25% of the island or about 3,400 ha. Control measures have so far been unable to eradicate this non-native species, but to date frigatebirds have not apparently been adversely affected by them. Less specific threats include over-fishing and marine pollution, plus clearance of vegetation and hunting on non-breeding roost islands^1,2,3. Approximately 10% of the population nests outside the national park and does not have any formal protection⁵. Clearance of vegetation within 300 m of nesting colonies should be avoided⁵. Frigatebirds are highly susceptible to entanglement in fishing gear, so intense fishing pressure in the South-East Asian waters and severe marine pollution there represent significant threats to the species⁶.

Conservation measures underway CITES Appendix I. Listed as vulnerable under the Environment Protection and Biodiversity Conservation Act 1999⁵. The Christmas Island National Park was established in 1980, and has since been extended to include two of the three current breeding colonies (90% of the population)¹. A recovery plan has been completed⁵ and there is an study since 2005 using radio telemetry to study movements¹⁵. A control programme for A. gracilipes was initiated after 2000 and effectively eliminated the ant from 2,800 ha of forest (95% of its former extent)¹. The ant population has increased significantly since then, upwards of 500 ha by 2006. Monitoring of the problem continues and hand-baiting measures have been ongoing. Aerial baiting was undertaken in September 2002 and proved to be successful against major colonies¹¹. Efforts are underway to find alternative bait that is not toxic to invertebrates on the island. The ants remained persistent in 2006, and perpetual baiting may be the only means of controlling them. There has been a suggestion of controlling the scale bugs that the ants tend for their sugar secretions in order to reduce this food supply¹⁰, but no formal proposal has been made, and there remains no evidence that they are adversely affecting frigatebird colonies.

Conservation measures proposed Implement the species recovery plan. Continue to control the abundance and spread of A. gracilipes. Develop and implement appropriate techniques to monitor the total/breeding population size and population structure⁵. Analyse existing data on breeding biology and success. Lobby to prevent mining close to colonies. Negotiate protection of all known and potential nesting habitat and appropriate buffers. If necessary, implement appropriate management in feeding habitat in South-East Asia to avoid bycatch etc. Maintain a quarantine barrier between Christmas Island and other lands to minimise the risks of new avian diseases establishing⁵.

References Garnett and Crowley (2000). 1. P. Green and D. O'Dowd in litt. (2003). 2. S. Garnett in litt. (2003). 3. James (2003). 4. Stokes (1988). 5. Hill and Dunn (2005). 6. James (2006). 7. James (2004). 8. J. Hennicke in litt. (2007). 9. James (2004b). 10. T. Low in litt. (2006). 11. Olsen (2005). 12. P. Green in litt. (2007). 13. Vromant and Chau (2007). 14. D. James in litt. (2007). 15. J. Hennicke in litt. (2008).

Further web sources of information

Alliance for Zero Extinction (AZE) species/site profile. This species has been identified as an AZE trigger due to its IUCN Red List status and limited range.

Australian Govt - Action Plan for Australian Birds 2000 - Recovery Outline

Fully detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001), together with new information collated since the publication of the Red Data Book

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Mike Crosby (BirdLife International), Stephen Garnett (Charles Darwin University), Stephen Garnett (Birds Australia), Ben Lascelles (BirdLife International), Rachel McClellan (BirdLife International), Andy Symes (BirdLife International), Joe Taylor (BirdLife International)

Contributors Stephen Garnett (Charles Darwin University), Peter Green (La Trobe University, Melbourne), Janos Hennicke (University of Hamburg), David James (Australian Museum), Tim Low (University of Queensland), Dennis O'Dowd (Monash University)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Andy Symes (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Fregata andrewsi. Downloaded from http://www.birdlife.org on 10/2/2010

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.

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