9.
Christmas Island Frigatebird
(Fregata andrewsi)
CR
Overview

The Christmas Island Frigatebird is the rarest endemic seabird on Christmas Island, Australia. It belongs to a family of five birds, the Fregatidae, which have the largest wingspan to body weight ratio of any bird. This bird has the ability to stay aloft for more than a week at a time allowing them to have a large foraging range. It spends a large proportion of time at sea, snatching prey from other birds and plucking squid and fish from the surface of the water. Its breeding habitat is affected by the invasive yellow crazy ant, while threats from habitat loss and pollution from phosphate mining still ongoing. Much of the breeding colony now lies within the Christmas Island National Park, but almost 10% of the population nests outside this area which does not have any formal protection. With such small numbers surviving, every individual counts and conservation measures must protect the entire population.

Urgent Conservation Actions
Extend national park to encompass the entire breeding colony, investigate population dynamics,foraging ecology and utilization of marine habitat.Control habitat loss and the spread of the yellow crazy ant. It is also recommended to examine the effects of climate change.
Distribution
Christmas Island and Indian Ocean.
Fact
With a huge wingspan of over two metres, this incredible seabird can remain airborne for over a week.
Media from ARKive
Arkive image - Juvenile Christmas frigatebird on nest
Arkive video - Christmas frigatebird - overview
Arkive video - Christmas frigate birds nesting and juvenile on nest.
Arkive image - Christmas frigatebird in flight
Arkive video - Christmas frigatebird male in courtship display
Arkive image - Christmas frigatebird in flight
Arkive video - Male Christmas frigate bird performing courtship display to watching female
Arkive image - Male Christmas frigatebird in flight
Arkive video - Christmas frigate birds in flight
Arkive image - Christmas frigatebirds interacting in flight
Arkive image - Christmas frigatebirds interacting in flight
Arkive image - Christmas frigatebird attacking brown booby
Arkive image - Christmas frigatebird drinking whilst in flight
Arkive image - Male Christmas frigatebird displaying
Arkive image - Christmas frigatebirds on the nest
Arkive image - Female Christmas frigatebird on nest
Arkive image - Female Christmas frigatebird on nest
Evolutionary Distinctiveness
Order: Pelecaniformes
Family: Fregatidae

The frigatebirds are a small family of five, closely-related species, grouped together in a single genus, Fregata. As they evolved into distinct species, these birds underwent only limited changes in morphology. The Fregatidae became a distinctive group at a very early stage, as indicated by fossil remains found in the United States of America dating back 50 million years. The Christmas Island Frigatebird has since remained a monotypic species. Recent DNA studies place these essentially non-swimming, highly aerial birds, close to the supremely aquatic penguins.

The tree below shows the evolutionary relationships between this species and all other birds. The colours of the tree indicate EDGE scores with the red shades indicating the higher priority species; the bright red leaves correspond to the top 100 EDGE bird species. Further information on every species can be found by zooming in to its leaf on the tree.
Description
Size: 
89-100cm
Weight: 1.2kg-1.7kg

With a wingspan of 205–230cm, frigatebirds have the largest wingspan to body weight ratio of any bird, able to stay aloft for more than a week. As with all frigatebirds the Christmas Island Frigatebird is sexually dimorphic. The adult male is mostly black (glossed with green) apart from a white belly patch. The bill is long, dark grey and hooked. The male has a large, red gular pouch, which is inflated during courtship. The female is generally larger than the male and has a white breast and belly. The upperparts are glossy black, like those of the male. The bill is pink and females lack the inflatable gular pouch. Both sexes have a pale bar on their upperwings and a long, deeply-forked tail. The legs are dull pink and females have pink feet whilst males have black feet. Juveniles have a complex series of plumages, with progressively less amounts of brown on the head and a white underbody.

Ecology

Their diet comprises flying fish, squid and other marine animals including seabird eggs and chicks. It feeds via surface dipping, strongly relying on aquatic predators to drive its prey to the surface. Another method it employs is kleptoparasitism – stealing other bird’s food by forcing them to regurgitate. It feeds in high temperature, low salinity waters mainly in the pelagic zone, often flying hundreds or thousands of kilometres on foraging trips. The frigatebird nests in tall trees, especially the Indian Almond (Terminalia catappa) and preferably in areas sheltered from the south-east trade winds. Nests are formed on a frail platform from loosely woven sticks or vines, mostly collected by the male. They form colonies, which are divided into groups of up to 20 nests due, primarily, to the limited nesting spots in a given tree. In each tree, up to 38 adjacent nests may occur, often less than one metre apart. The nesting season occurs from March to May and parents may only raise one fledgling every two years. Both sexes take part in incubation, switching every few days. This is a monogamous species, although it probably acquires a new mate each breeding season.

Habitat
This species spends most of its time foraging out on the open ocean, in the warm, low-salinity waters of the Indian Ocean. Preferred breeding habitat is tall forest on shore terraces. It favours trees that are of the Terminalia catappa and Celtis timorensis species for its nest.
Distribution
This species is endemic to Christmas Island, Australia, which is situated in the Indian Ocean approximately 500km south of Jakarta, Indonesia. In the non-breeding season it is found foraging at low densities throughout the Indo-Malay archipelago, including Brunei Darussalam, Cambodia, China, Christmas Island, Hong Kong, Indonesia, Malaysia, Singapore, Sri Lanka, Thailand and Timor-Leste.
Population Estimate
2400–4800 adults
Population Trend
Declining
Status
Critically Endangered
Threats

The introduced yellow crazy ant, Anoplolepis gracilipes, could be a serious threat to the Christmas Island Frigatebird. This invasive ant forms huge super-colonies preying on insects, earthworms, crabs, mammals, birds and reptiles. It was feared that these ants may feed on chicks or cause nest abandonment, but no adverse effects on the frigatebird have been recorded. The yellow crazy ant kills red crabs, which are essential for the island’s ecology, turning over and fertilising soil. The ants also ‘farm’ sugar-producing, sap-sucking insects, which can damage forest canopies and cause tree death. So indirectly this invasive species may be having an impact on the frigatebird’s breeding habitat. Almost 25% of the nesting area was cleared for phosphate mining in the early 1900s. Mining proposals are still being put forward and in 2007, several patches of secondary forest were cut down for this purpose. One tenth of the frigatebird population breeds in unprotected areas outside the national park. The effect of marine pollution and decreasing fish stocks is yet to be quantified, but frigatebirds are known to become entangled in fishing nets.

Conservation Underway
This species is listed under CITES Appendix I. The Christmas Island National Park was established in 1980, and has since been extended to include two of the three current breeding colonies. The recovery plan that was drafted in 2004 has been completed and satellite tracking has been used to track the birds movements. Despite crazy ant control measures in 2002, that eradicated 98% of the population, the quick recovery rate of the ants means this invasive species is still a problem today. The aerial bait used to control the ant was discovered to be toxic to invertebrates and no other effective alternative has found. One option could be to curtail the ant’s sugar supply by controlling the sap-sucking bugs they farm. An ant control programme continues with hand-baiting. Monitoring of this alien species will enable any future outbreaks to be treated without delay. A survey of seabirds on Christmas Island was implemented in 2010.
Conservation Proposed

Accurate assessments of this species population size and dynamics need to be undertaken, as does analysis of current data. The spread of the yellow crazy ant needs to be monitored and numbers controlled, particularly around Christmas Island Frigatebird nesting sites. Relationships with phosphate mining companies need to be developed, so that negotiations can be made to protect habitat and create buffer strips. Implementation of a community education programme would be beneficial, as would a wildlife management plan for frigatebird habitat outside the national park. The risk of foreign bird diseases spreading from neighbouring countries needs to be negated by establishing a quarantine barrier.

Links
References
BirdLife International (2012). Fregata andrewsi. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. www.iucnredlist.org. Downloaded on 03 June 2013.

BirdLife International (2013) Species factsheet: Fregata andrewsi. Downloaded from www.birdlife.org on 3/06/2013

Collar, N. J., Crosby, R. and Crosby, M. J. (2001). Threatened Birds of Asia: The BirdLife International Red Data Book. Cambridge, U.K. BirdLife International.

del Hoyo J., Elliott, A. and Sargatal, J. (1992). Handbook of the Birds of the World: Volume 1: Ostrich To Ducks. Lynx Edicions.

Garnett, S. T. and Crowley, G. M. (2000). The action plan for Australian birds 2000. Canberra: Environment Australia.

Hill, R. and Dunn A. (2004). National Recovery Plan for the Christmas Island Frigatebird Fregata andrewsi. Commonwealth of Australia, Canberra.

James, D. J. (2004). Identification of Christmas Island, Great and Lesser Frigatebirds. Birding Asia, 1, 22-38.

Loss of Biodiversity and Ecosystem Integrity Following Invasion by the Yellow Crazy Ant (Anoplolepis gracilipes) on Christmas Island, Indian Ocean. Australian Government: Department of the Environment, Water, Heritage and the Arts.

Marchant, S. and Higgins, P. J. (1990). Handbook of Australian, New Zealand and Antarctic Birds. Vol. 1. Oxford University Press, Melbourne.

Stokes, T. (1988). A Review of the Birds of Christmas Island, Indian Ocean. ANPWS Occasional Paper No. 16. ANPWS, Canberra.
Acknowledgements
Text compiled by Michelle Harrison. Factchecked by Janos Hennicke .

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