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Abbott's booby (''Papasula abbotti'') is an endangered
seabird Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...
of the sulid family, which includes
gannet Gannets are seabirds comprising the genus ''Morus'' in the family Sulidae, closely related to boobies. They are known as 'solan' or 'solan goose' in Scotland. A common misconception is that the Scottish name is 'guga' but this is the Gaelic n ...
s and
boobies A booby is a seabird in the genus ''Sula'', part of the family Sulidae. Boobies are closely related to the gannets (''Morus''), which were formerly included in ''Sula''. Systematics and evolution The genus ''Sula'' was introduced by the Fre ...
. It is a large booby and is placed within its own
monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...
genus. It was first identified from a specimen collected by William Louis Abbott, who discovered it on
Assumption Island Assumption Island is a small island in the Outer Islands of Seychelles north of Madagascar, southwest of the capital, Victoria. In 2018, Seychelles and India signed an agreement to build and operate a joint military facility on a portion of ...
in 1892. Abbott's booby breeds only in a few spots on the Australian territory of
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 ...
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), ...
, although it formerly had a much wider range. It has white plumage with black markings, and is adapted for long-distance flight. It forages around Christmas Island, often around nutrient-rich oceanic
upwelling Upwelling is an physical oceanography, oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted sur ...
s, although individuals can travel for thousands of kilometres. Pairs mate for life and raise one chick every two or three years, nesting near the top of emergent trees in the rainforest canopy. The population is decreasing. Historically, much of its former habitat was logged to make way for
phosphate Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...
mining. Some logging continues, and the effects of the former logging continue to adversely affect the current population. Another threat has been caused by the introduction of yellow crazy ants, which decrease habitat quality. Minimal habitat declines have a significant effect on the bird population. All nesting areas have been included in a
national park A national park is a nature park designated for conservation (ethic), conservation purposes because of unparalleled national natural, historic, or cultural significance. It is an area of natural, semi-natural, or developed land that is protecte ...
.


Taxonomy

The first specimen was collected from Assumption Island in 1892 by American naturalist William Louis Abbott, northwest of Madagascar, although debate exists as to whether he actually collected it from the nearby Glorioso Island. It was described by
Robert Ridgway Robert Ridgway (July 2, 1850 – March 25, 1929) was an American ornithologist specializing in systematics. He was appointed in 1880 by Spencer Fullerton Baird, secretary of the Smithsonian Institution, to be the first full-time curator of birds ...
in 1893. In 1988, it was placed in its own genus by Olson & Warheit 1988. The basal characters present in this species suggest it may be an early branch of the sulid family, antedating the split between gannets and other boobies. This was reinforced by analysis of the mitochondrial cytochrome ''b'' gene in 1997, which indicated Abbott's booby was an early offshoot of the gannets rather than the other boobies. However, 2011 study of multiple genes found it to be basal to all other gannets and boobies, and likely to have diverged from them around 22 million years ago. A
subfossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
subspecies from the
Mascarene Islands The Mascarene Islands (, ) or Mascarenes or Mascarenhas Archipelago is a group of islands in the Indian Ocean east of Madagascar consisting of islands belonging to the Republic of Mauritius as well as the French department of Réunion. Their na ...
of
Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...
and
Rodrigues Rodrigues ( ; Mauritian Creole, Creole: ) is a Autonomous administrative division, autonomous Outer islands of Mauritius, outer island of the Republic of Mauritius in the Indian Ocean, about east of Mauritius. It is part of the Mascarene Isl ...
was named '' P. a. nelsoni'' in 2023. The subspecies are: * P. a. abotti (Christmas island booby) * P. a. nelsoni (Mascarene booby)


Description

Abbott's booby is the largest of all booby species, and is adapted to long-distance flight. Individuals can reach from beak to tail, and weigh about . It is distinguished from other sulids in the region by its black and white plumage; the only other bird with similar coloration and shape is the
masked booby The masked booby (''Sula dactylatra''), also called the masked gannet or the blue-faced booby, is a large seabird of the booby and gannet family, Sulidae. First described by the French naturalist René-Primevère Lesson in 1831, the masked boob ...
, which has an all-white body with black wings only. They have an off-white plumage, which contrasts with black eye patches, black wings and tails, and black flank marks. Their feet are blue and webbed, with black outer ends. Males have pale grey bills with a black tip, whereas females have pink bills with a black tip. Chicks have white down and a cape of black scapular feathers. Juvenile birds have plumage similar to adults, unlike other species of boobies.


Distribution and habitat

Abbott's booby is the only booby restricted to a single location, although its former distribution covered much of the Indian and Pacific Oceans. Fossil evidence indicates its former presence in the South Pacific, and eyewitness reports of it formerly breeding on the
Mascarene Islands The Mascarene Islands (, ) or Mascarenes or Mascarenhas Archipelago is a group of islands in the Indian Ocean east of Madagascar consisting of islands belonging to the Republic of Mauritius as well as the French department of Réunion. Their na ...
. In April 2007, an individual of this species was photographed at a booby colony on Rota in the Pacific Ocean, and the same individual has been seen off-and-on in the
red-footed booby The red-footed booby (''Sula sula'') is a large seabird of the booby family, Sulidae. Adults always have red feet, but the colour of the plumage varies. They are powerful and agile fliers, but they are clumsy in takeoffs and landings. They are ...
colony there through at least 2024. It breeds in tall trees in the plateau forests of the central and western areas of Christmas Island, and in the upper terrace forests of the north coast. Nest distribution is patchy, based on topography, with the majority of nests in trees on uneven terrain. Nests are usually built on '' Syzygium nervosum'' and '' Planchonella nitida'' trees, although emergent '' Tristiropsis acutangula'' trees are sometimes used. Due to the
trade wind The trade winds or easterlies are permanent east-to-west prevailing winds that flow in the Earth's equatorial region. The trade winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere, ...
s flowing south-east from April to November, trees that can be approached from the northwest are favoured. Its foraging range usually reaches from Christmas Island, although individuals are often seen in Indonesia and vagrants reach as far as mainland Australia. A single female was recently observed on Rota, northeast of Guam in the Pacific, and some records from the
Banda Sea The Banda Sea (, , ) is one of four seas that surround the Maluku Islands of Indonesia, connected to the Pacific Ocean, but surrounded by hundreds of islands, including Timor, as well as the Halmahera Sea, Halmahera and Ceram Seas. It is about ...
indicate either an even larger range or unknown breeding colonies.


Population

The Abbott's booby population is the best documented, and smallest, of all sulid populations. It was first assessed in 1967, resulting in an estimate of 2,300 breeding pairs. By 1983, the number of breeding pairs had declined to 1,900. The most comprehensive survey was made in 1991, and included new breeding sites that were unknown in previous surveys. It brought the estimate of breeding pairs up to 2,500, with the total number of mature individuals being placed at 6,000. A helicopter survey in 2002 noted 1,500 nest sites. The population was stable from 1991 to 2002. The population size is estimated to decrease more than 80% over the next three generations, or 120 years. The current decline is attributed to a low recruitment rate and the negative effects of wind turbulence on a breeding population. Due to its small population, limited habitat, low fecundity, and limited distribution, Abbott's booby is at high risk of extinction if further habitat disturbance occurs.


Ecology

Individuals are solitary, long-distance travellers that can range thousands of kilometres from Christmas Island. They are very vocal, with a wide range of calls. Due to their size, they require a large clear space to take off. So, they nest near the tops of trees. If an individual falls to the forest floor, it will starve unless it can climb high enough to be able to catch the wind and take off. Adults rarely fight owing to the risk of falling. Fledglings must succeed in their first attempt at flight; unsuccessful attempts rarely result in the fledgling's survival. Adults forage at sea from October to April, although they return if they have a chick that is dependent on them. They forage in offshore waters, eating fish and squid. No feeding patterns are known, although they are thought to forage in an ocean
upwelling Upwelling is an physical oceanography, oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted sur ...
off
Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...
, northwest of Christmas Island. Chicks are fed through complete regurgitation for the first two weeks, then incomplete regurgitation. Both parents feed the young.


Breeding

Courtship takes the form of a face-to-face display. Partners mate for life, and maintain the same nest site throughout their lives. Nests are made near the top of rainforest trees, off the ground, usually at elevations of or higher. Breeding cycles last 15–18 months, and only one
egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...
is laid during each cycle. Successful pairs can nest once every two years, but often take rest years between attempts to raise a chick. These rest years are taken even if the couple is unsuccessful in raising their chick. Most pairs only breed once every three years. Mating usually takes place in April, and eggs are laid between April and July. Eggs are equal to 8% of the female's body weight. They are incubated under the webbed feet of the parents, which become vascularised and warm. Incubation is undertaken by both parents, which take shifts of up to two days. Eggs are incubated for about 56 days, which is 30 days longer than in other sulids. Chicks hatch from June to November, after the eggs are incubated around 56 days. They take 170 days to fully fledge, and an additional 200 days to become fully independent. Most chicks make their first flight in December or January.Marchant, S.; & Higgins, P.J. (Eds). (1990). '' Handbook of Australian, New Zealand and Antarctic Birds. Volume 1: Ratites to Ducks''. Oxford University Press: Melbourne. Nelson, J. Bryan. (1978). ''The Sulidae. Gannets and Boobies''. Oxford University Press: Oxford. Fledglings reach maturity around eight years of age, and can live up to 40 years.


Threats and conservation

Even a minimal decline in habitat quality can have a significant impact on these birds. During 1965–1987, phosphate mining destroyed one-third of the Abbott's booby's nesting habitat. Degeneration has continued, with the health of individual trees decreasing. Clearings left over from logging have increased wind in the canopy, generating turbulence up to downwind of the clearings. This causes lower breeding success due to chicks being dislodged and not surviving their first flight. Adult survival is also reduced due to increased risk of them falling to the ground when landing. This affects 36% of the current population. Introduced plants are foiling habitat rehabilitation in abandoned mining sites and pose a risk if they invade primary forest. Continued mining remains an issue, with mature secondary forest cleared for mining in 2007. A request to mine in what is currently 250 half of forest was turned down in 2007, but is under appeal. Christmas Island Phosphates Pty Ltd. may not clear primary forest, and requires a permit to clear regrowth.
Christmas Island National Park Christmas Island National Park is a national park occupying most of Christmas Island, an Australian territory in the Indian Ocean southwest of Indonesia. The park is home to many species of animal and plant life, including the eponymous Christma ...
includes all known Abbott's booby nest sites. It was created in 1980 and was subsequently expanded to cover 60% of the island. The population was monitored from 1982 to 1993, and in 1984, 20% of mined areas next to nesting sites had been replanted. The Environment Australia Abbott's Booby Recovery Plan aims to regenerate forests and help prevent further decline in the species. Forest rehabilitation has now been attempted in about 30% of abandoned mining areas, with a focus on areas close to primary forest where new growth could act as a wind break. Most of the planted trees are foundation species, with non-native species being used if they do not invade the environment. Part of the forest regeneration project is financed by the phosphate mining company as part of their lease agreement. An invasion of the yellow crazy ant poses continued risk for the booby population. Yellow crazy ants formed supercolonies in the 1990s and spread throughout 28% of the island's forest. Starting in 2000, efforts to control it eliminated it from 2,800 ha of forest, resulting in a 95% reduction of its range. The range was 300 ha in 2005, at much lower densities than originally, although it has slightly recovered since then. The ants could prey on nestlings and cause nest abandonment, although this has not been observed. They do, however, disrupt the ecosystem by killing red crabs, and farm
scale insect Scale insects are small insects of the Order (biology), order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient g ...
s that damage the trees where the boobies nest.
Overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing Fish stocks, fish stock), resu ...
and
marine pollution Marine pollution occurs when substances used or spread by humans, such as industrial waste, industrial, agricultural pollution, agricultural, and municipal solid waste, residential waste; particle (ecology), particles; noise; excess carbon dioxi ...
pose additional problems for the population. The birds may be directly hunted or caught as bycatch in
longline fishing Longline fishing, or longlining, is a commercial fishing angling technique that uses a long ''main line'' with baited hooks attached at intervals via short branch lines called ''snoods'' or ''gangions''. as they may come into contact with Indonesian and Taiwanese fisheries. This has not been documented. Plans for a satellite launch pad to be built on the island have been discussed, but are not currently being put into action. In 1988, a cyclone destroyed a third of all nests and fledglings. Climate change resulting in increased sea surface temperatures, changes in rainfall patterns, and changes in the
El Niño Southern Oscillation EL, El or el may refer to: Arts and entertainment Fictional entities * El, a character from the manga series ''Shugo Chara!'' by Peach-Pit * Eleven (''Stranger Things'') (El), a fictional character in the TV series ''Stranger Things'' * El, fami ...
may further damage the population due to changing weather patterns. The increase in sea temperatures reduces breeding success, as the best feeding is found in cold water caused by nutrient-rich upwellings. Abbott's booby is listed under
CITES CITES (shorter acronym for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of inte ...
Appendix I, and is classified as endangered in the
IUCN Redlist The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological spe ...
. It is also classified as endangered under the Australian
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 ...
. Many Abbott's boobies are in the National Park, so their nests are monitored.


References


Further reading

*


External links


Australian Government's 2000 Recovery Outline

National recovery plan
{{Authority control Sulidae Boobies Birds of Christmas Island Birds described in 1893 Endangered fauna of Australia Endangered fauna of Oceania Taxa named by Robert Ridgway