Data Zone
Justification of Red List category
This species has a population numbering fewer than 5,000 mature individuals and is estimated to be in continuing decline, principally because of persecution by fishing activities in Indonesia. It is therefore listed as Vulnerable.
Population justification
There have been five estimates in the last three generations: 1,300 pairs in 1985 (Stokes 1988), 1,466±325 in 2003, 1,392±102 in 2004 (James 2014), 1,050 in 2016 and 1,200 in 2017 (J.C. Hennicke unpublished). Taking a different approach based on genetics, Morris-Pocock et al. (2012) estimated the population at 5,000 mature individuals. The best estimate of mature individuals is the mean of the two methods.
Trend justification
Historically, there were estimated to be 6,300 annual breeding pairs, but a loss of breeding habitat apparently owing to habitat clearance and dust fallout from phosphate mining, marine pollution, overfishing and bycatch in fishing gear has caused declines. Although land-based threats are no longer thought to be prevalent, declines are projected to continue principally owing to the ongoing threat of persecution by fishing activities (Macgregor et al. 2021). Surveys from 2008-2013 show an ongoing declining trend in breeding numbers (Hennicke 2014). There have been five estimates in the last three generations: 1,300 pairs in 1985 (Golf Course 850 nests, Cemetery 350, Dryers 100; Stokes 1988), 1,466±325 in 2003, 1,392±102 in 2004 (James 2014), 1,050 in 2016 and 1,200 in 2017 (J. C. Hennicke unpublished, in Macgregor et al. 2021). This species breeds biennially, so the increase between 2016 and 2017 cannot be interpreted as an increase in mature individuals. Using the five estimates of breeding pairs, there was an approximate decline of c.20-25% over the last three generations (Macgregor et al. 2021).
This species is endemic as a breeding species to Christmas Island (Australia), in a few small patches of forest near the Golf Course, Flying Fish Cove, the Cemetery and Margaret Beaches with small numbers of nests in the Settlement, Smith Point and west of Margaret Beaches (James and McAllan 2014, Commonwealth of Australia 2020). At sea, they commonly travel to Javan coastal waters when breeding (Hennicke et al. 2015). After breeding, frigatebirds travel widely among the islands to the north-east of Christmas Island (James and McAllan 2014, Hennicke et al. 2015, Tirtaningtyas and Hennicke 2015).
Breeding and non-breeding birds have been recorded foraging at low densities in the Indo-Malay Archipelago (James 2004) over the Sunda Shelf to the South China Sea, the Andaman Sea, the Sulu Sea, off south-west Sulawesi, off south-west Thailand and in the Gulf of Thailand (Catterall 1997, Vromant and Chau 2007, D. James in litt. 2007, Tebb et al. 2008, Conlin 2013), commuting directly over Java in the process (James 2006, Hennicke et al. 2015). The seas around West Java, Indonesia seem to be important during the non-breeding season, especially in Jakarta Bay, where 100-200 individuals were recorded in one day (Noni 2012, Burung Laut Indonesia 2013). Pulau Rambut Wildlife Reserve (one of the island in Jakarta Bay) is a roosting site for Christmas Island and Lesser Frigatebirds (Wardhani 2011). When not breeding the species ranges widely across the seas of South-East Asia to Indochina and south to northern Australia (Stokes 1988, Hennicke et al. 2015). The species's status in the Indian Ocean to the west is generally less well known, however one individual was recorded off the coast of Kanyakumari district, southern India in 2014 (Arivanantham 2014).
Christmas Island Frigatebirds breed biennially, nesting high in tall trees mainly on the coastal terraces along the north coast, sheltered from the prevailing south-eastern trade winds (Hill and Dunn 2004, James and McAllan 2014). During breeding, they forage over pelagic waters as well as Indonesian coastal areas for flying fish, squid and other marine species driven to the sea surface by large subsurface predators, such as tuna and dolphins (Hill and Dunn 2004, Hennicke et al. 2015). When not breeding they relocate to small uninhabited islands in Southeast Asia where they forage locally over shallower coastal waters with variable salinity and turbidity (James and McAllan 2014, Hennicke et al. 2015). It is assumed to be able to occupy all elevations on the island, up to the maximum elevation of 357 m, although most of the breeding colonies are at lower elevations.
Human persecution represents a major threat to this species due to direct targeting by fishermen in Indonesia and Malaysia (shooting, live catching, sedating and poisoning). It also suffers from accidental entanglement in fishing gear associated with the intense fishing pressure in South-East Asian waters causing slow but significant population declines (Burung Laut Indonesia 2013, Hennicke 2014, Tirtaningtyas and Hennicke 2015). Overfishing of large predatory fish that drive frigatebird prey to the surface has the potential to cause food shortages (Commonwealth of Australia 2020). Marine pollution represents another significant threat to the population (James 2006, Noni 2012). Included in the species’ range are inshore waters with high levels of contamination from heavy metals and a variety of other industrial pollutants, but the impacts of pollution on the species are currently unknown (Tirtaningtyas and Yordan 2017). Waste disposal and pollution produced by several activities (e.g. industry, recreation and sport) are potential threats, as recorded in the important foraging grounds of Jakarta Bay (Arifin 2004).
Historically, clearance of forest and dust pollution from phosphate mining and other development may have reduced the population on Christmas Island or forced birds to nest in other areas (Stokes 1988, James 2003, James and McAllan 2014), but at the time of writing no clearing of the island's old-growth forest (primary vegetation) has been permitted since 1988. Currently, land-based threats are unlikely to be causing population declines: although weeds could affect some breeding areas in the long term if not controlled, and burning off on the golf course, ingestion of plastic (Commonwealth of Australia 2020) and infection with Hemosporidian blood parasites (Quillfeldt et al. 2010, Merino et al. 2012) may affect some individuals, they have not been linked to declines. Extreme weather, habitat shifts and ecosystem degradation associated with climate change poses an ongoing and future threat to the species. Demonstrated effects of increased sea surface temperatures and decreased marine productivity on the foraging of Abbott’s Boobies around Christmas Island (Hennicke and Weimerskirch 2014), suggest that the impacts of climate change are already affecting the seabird food chain in the Christmas Island Frigatebird’s breeding range. Threats currently considered negligible include drowning in artificial water bodies and heavy metal contamination (Commonwealth of Australia 2020), that the productivity of marine systems in the region may decline as a result of climate change (Bryndum-Buchholz et al. 2019) potentially depleting tuna populations (Dueri 2017), and the threat posed by vines smothering one of the few roost sites available on the roost island in Jakarta Bay, Indonesia (F. Tirtaningtyas pers. comm.).
Another possible threat is the invasive yellow crazy ant Anoplolepis gracilipes, which formed super-colonies during the 1990s and spread rapidly to cover about 25% (3,400 ha) of Christmas Island. Control measures have so far been unable to eradicate this non-native species, but to date Frigatebirds do not appear to have been adversely affected (Hennicke 2014). However, ant super-colonies alter island ecology by killing the dominant life-form, the red crab Gecaroidea natalis, and by farming scale insects which damage the trees. This may alter the breeding habitat of the species in the medium- to long-term (J. Hennicke in litt. 2010). Currently, there are only four significant nesting colonies of Christmas Island Frigatebirds (James and McAllan 2014). Considerable areas of former breeding habitat have already been cleared and the species was likely more numerous prior to this loss of habitat (Hill and Dunn 2004). The low number, limited extent and reduced size of breeding areas render the species highly susceptible to stochastic events and vulnerable to further habitat loss, either through resumed mining operations, other sources of pollution or climate change.
Conservation Actions Underway
CITES Appendix I. Listed as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999 (Hill and Dunn 2004). 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) (P. Green and D. O'Dowd in litt. 2003). A recovery plan has been completed (Hill and Dunn 2004) and a study using satellite telemetry and GPS loggers to study movements has been underway since 2005 (J. Hennicke in litt. 2008, 2010; Hennicke et al. 2015). A control programme for A. gracilipes was initiated after 2000 (P. Green and D. O'Dowd in litt. 2003), and plans have been established to control the scale bugs that the ants tend for their sugar secretions in order to reduce this food supply, but there remains no evidence that the ants are adversely affecting frigatebird colonies (Hennicke 2014, J. Hennicke in litt. 2010). A census of the breeding population on Christmas Island is currently being undertaken (J. Hennicke pers.comm. 2016). In 2014 and 2016, the Indonesian government had a conservation plan to assess seabird bycatch. Investigations under way in Jakarta Bay on trends in frigatebird weights.
Conservation Actions Proposed
Develop and implement appropriate techniques to monitor the total/breeding population size, population structure and rate of decline (Hill and Dunn 2004, Hennicke 2014). Undertake year-round monitoring in the Jakarta Bay area (Burung Laut Indonesia 2013). Understand importance of Sunda Straits as a migration corridor for the species (Burung Laut Indonesia 2013). Analyse existing data on breeding biology and success and investigate movements and habitat use. Continue tracking of adults and juveniles to identify foraging habitat and model population size and trend (Hennicke 2014, Hennicke et al. 2015). Assess threats to the species in both these areas and identify and protect important sites. Research the threats to the species off Christmas Island and the impact of mortality in Indonesian and Malaysian waters on the population size (Hennicke 2014, Tirtaningtyas and Hennicke 2015). Determine the extent of losses to hunting and bycatch. Develop and implement appropriate management in feeding habitat in South-East Asia to avoid bycatch and hunting. Undertake a biosecurity risk assessment to identify disease risk. Implement the species recovery plan.
Negotiate protection of all known and potential nesting habitat and appropriate buffers. Ensure no further habitat is lost. Continue to control the abundance and spread of A. gracilipes. Ensure breeding habitat is secure from weeds and disturbance. Maintain and strengthen biosecurity measures to prevent avian disease and invasive species incursions. Maintain a quarantine barrier between Christmas Island and other lands to minimise the risks of new avian diseases establishing (Hill and Dunn 2004). Lobby to prevent mining close to colonies. Collaborate with Indonesian authorities and non-government organisations to reduce losses from hunting.
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 (2004a) for detailed notes on identifying frigatebirds.
Text account compilers
Martin, R., Berryman, A., Vine, J.
Contributors
Ashpole, J, Benstead, P., Bird, J., Calvert, R., Crosby, M., Fjagesund, T., Garnett, S., Green, P., Hennicke, J., James, D., Lascelles, B., Low, T., McClellan, R., Moreno, R., O'Dowd, D., Symes, A., Taylor, J., Tirtaningtyas , F. & Westrip, J.R.S.
Recommended citation
BirdLife International (2024) Species factsheet: Christmas Island Frigatebird Fregata andrewsi. Downloaded from
https://datazone.birdlife.org/species/factsheet/christmas-island-frigatebird-fregata-andrewsi on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.