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Papasula abbotti

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA AVES SULIFORMES SULIDAE

Scientific Name: Papasula abbotti
Species Authority: Ridgway, 1893
Common Name(s):
English Abbott's Booby
Spanish Alcatraz de Abbott, Piquero de Abbott
Synonym(s):
Sula abbotti abbotti Collar and Andrew (1988)

Assessment Information [top]

Red List Category & Criteria: Endangered B2ab(ii,iii,v) ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Garnett, S., Green, P., Hennicke, J., James, D., Jeffery, M., Low, T. & O'Dowd, D.
Facilitator/Compiler(s): Benstead, P., Calvert, R., Crosby, M., Garnett, S., Harding, M., McClellan, R., Taylor, J.
Justification:
This species breeds in the limited suitable habitat of just one area of a very small island, and it has a small population which has declined rapidly owing to the effects of past habitat clearance. Recent die-back of some of the breeding habitat indicates that habitat quality continues to decline, although it is unclear whether this die-back has been caused by introduced yellow crazy ants. Because of the significance of even minimal declines in habitat quality within the limited breeding habitat of this booby, it is listed as Endangered.

Geographic Range [top]

Range Description: Papasula abbotti breeds only on Christmas Island (to Australia), though it once had a much wider distribution in the Indian and Pacific Oceans. One female was recently observed on Rota Island (Northern Mariana Islands to USA), though it is not known whether it is vagrant or a solitary resident (Pratt et al. 2009). The population was estimated at 2,300 pairs in 1967, declining to 1,900 pairs by 1983. Newly discovered breeding sites brought the total to an estimated 2,500 active pairs, following a survey in 1991 (Yorkston and Green 1997), which is regarded as the most accurate and comprehensive to date (James 2007). A helicopter survey in 2002 recorded about 1,500 active nest sites (Commonwealth of Australia 2004), but the results were not verified by ground-based surveys (James 2007). Overall, it seems that the breeding population was more or less stable between 1991 and 2002 (Commonwealth of Australia 2004, P. Green per D. James and M. Jeffery in litt. 2005), but the survey techniques are not directly comparable (D. James in litt. 2005, 2007, James 2007). The species's breeding cycle takes 15-18 months, meaning that successful pairs nest once every two years whilst unsuccessful pairs may breed in successive years or take 'rest years', thus only a proportion of the breeding population breeds in a given year, and this is dependent on nesting success in the previous year (James 2007). Thus in 2000, following on from the 1991 survey, the total population of mature individuals was put at c.6,000. It disperses within the Indian Ocean. Recent records from the Banda Sea indicate either a major extension of its known range or unknown breeding colonies.

Countries:
Native:
Christmas Island; Indonesia
Regionally extinct:
Mauritius; Seychelles
Vagrant:
Australia
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Following an estimate of 2,500 active pairs in 1991, the total number of mature individuals has been put at c.6,000, equating to c.9,000 individuals in total. It should be noted that only a proportion breed in a given year owing to a 15-18 month breeding cycle and the possibility that some unsuccessful pairs take 'rest years' rather than breed in successive years. Despite a helicopter survey in 2002, the 1991 survey is considered the most accurate and comprehensive.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: It nests in tall rainforest trees, mostly above 150 m elevation in the western, central and northern areas of Christmas Island (Commonwealth of Australia 2004), and lays one egg. Most successful parents can only breed biennally. It may first breed at eight years of age, and its average lifespan may be c.40 years. It feeds at sea on squid and fish. The at sea distribution of this species is poorly known. It was previously thought that cold water upwellings south of Java could be important feeding areas for breeding boobies (Commonwealth of Australia 2004, Olsen 2005), however tracking studies seem to indicate that they simply forage within 40-100 km of Christmas Island and show no association with any clear oceanographic features (D. James in litt. 2005, 2007).

Systems: Terrestrial; Marine

Threats [top]

Major Threat(s): During 1965-1987, phosphate extraction resulted in the destruction of approximately one third of nesting habitat. Some trees in nesting areas have degenerated, but the extent of this is unquantified (D. James in litt. 2005, 2007). In addition, exotic plants that have colonised and been introduced to old mine sites may invade existing forest and threaten habitat rehabilitation (Commonwealth of Australia 2004, Olsen 2005). Future habitat loss is possible through clearance for mining (S. Garnett in litt. 2003). In 2007, significant patches of mature secondary forest were cleared for mining (D. James in litt. 2005, 2007). Alsoin 2007, a new application to mine a 250 ha area of rainforest (P. Green in litt. 2007) was turned down (J. Hennicke in litt. 2007), but has subsequently gone to appeal (D. James in litt. 2005, 2007). Plans for a satellite launch pad on the island are not proceeding at present (T. Low in litt. 2006). The effect of satellite launches on this species is unknown (Commonwealth of Australia 2004, Olsen 2005). Breeding boobies are vulnerable to extreme weather events. In 1988, a cyclone destroyed a third of monitored fledglings and nest-sites. In wind-affected areas, increased turbulence causes higher adult mortality and reduces fledging success. Artificial forest clearings, e.g. for roads and buildings, also cause wind turbulence. Possibly the most serious threat is the introduced yellow crazy ant Anoplolepis gracilipes which formed super-colonies during the 1990s and spread rapidly to cover 28% of the forest on the island. However, control efforts have been successful (P. Green and D. O'Dowd in litt. 2003), and at the beginning of 2005 there were an estimated 300 ha with A. gracilipes present on Christmas Island, with densities considerably lower than prior to control (D. James and M. Jeffery in litt. 2005). Despite the successes, in 2006 the ants were regarded as widespread and patchily common (T. Low in litt. 2006). Allowed to spread uncontrolled ant super-colonies may prey directly on nestlings or cause nest abandonment. However, there have been no observations of ants preying on the species, and comparison of ant distribution and densities with P. abbotti distribution showed no sign of nest abandonment in ant-infested areas (D. James and M. Jeffery in litt. 2005). Super-colonies alter island ecology by killing the dominant life-form, the red crab Gecaroidea natalis, and by farming scale insects which damage trees. A. gracilipes occurs from below ground-level to the canopy where P. abbotti nests. There are signs of forest die-back in a small area of breeding habitat, which may be indirectly caused or exacerbated by A. gracilipes, but its impact is unlikely to be severe (D. James and M. Jeffery in litt. 2005). Less specific threats include over-fishing and marine pollution. In addition, climate change may threaten the species through changes to sea surface temperatures, rainfall patterns and El Niño Southern Oscillation (Commonwealth of Australia 2004, Olsen 2005), although it is unlikely to be affected by sea level rise as it nests above 100 m (D. James in litt. 2005, 2007). At sea, birds may suffer from direct hunting and bycatch, but this has not been documented (Commonwealth of Australia 2004, Olsen 2005). If some birds feed close to Java this could bring them into contact with Taiwanese and Indonesian fisheries (Olsen 2005).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
CITES Appendix I. A national park was created in 1980, which has since been extended to cover more than 60% of the island (D. James in litt. 2005, 2007) and includes most breeding areas. A lease agreement with Christmas Island Phosphates Pty Ltd prevents clearance of primary rainforest and requires permits to clear regrowth. A monitoring programme was in place between 1982 and 1993. Since 1984, c.20% of mined areas adjacent to nesting areas have been planted in an ongoing restoration programme. A control programme for A. gracilipes has been successfully initiated since 2000 and effectively eliminated the ant from 2,800 ha of forest (95% of its former extent) (P. Green and D. O'Dowd in litt. 2003). Monitoring of the problem continues and hand-baiting measures have been ongoing. Aerial baiting was carried out in September 2002 and proved to be successful against major colonies (Olsen 2005), eliminating over 98% of ants (D. James in litt. 2005, 2007). However, the ants have since recovered (D. James in litt. 2005, 2007). The ants remained persistent in 2006, and it was thought that perpetual baiting would be the only means of controlling them (T. Low in litt. 2006). The bait used so far is known to be toxic to invertebrates, including crabs, and although alternatives have been trialled, an effective replacement has not been found (D. James in litt. 2005, 2007). Control of the scale bugs that the ants tend for their sugar secretions has been suggested, in order to reduce this food supply (T. Low in litt. 2006, D. James in litt. 2005, 2007). In 2004, 2005 and 2006, surveys were carried out to assess the impact of the construction of an immigration centre on a breeding colony adjacent to the site (James 2007).

Conservation Actions Proposed
Monitor the abundance and spread of A. gracilipes (Commonwealth of Australia 2004) whilst continuing to implement control measures. Develop and implement appropriate monitoring techniques (Commonwealth of Australia 2004). Monitor impact of rehabilitation efforts on trends and distribution. Identify feeding habitat of breeding adults and juveniles (by satellite tracking studies) (Commonwealth of Australia 2004, Olsen 2005). Negotiate with the mining company to ensure protection of all breeding habitat and appropriate buffers. Minimise and monitor effects of developments such as the launch pad (Commonwealth of Australia 2004). Develop a wind turbulence model to guide habitat restoration (Commonwealth of Australia 2004). Continue to implement weed management strategy (Commonwealth of Australia 2004). Monitor likely impact of developing fisheries around Christmas Island (Commonwealth of Australia 2004). Address threats from global climate change at national and international levels (Commonwealth of Australia 2004). Monitor the possible effects of climate change on the species (Commonwealth of Australia 2004). Protect nest cluster (c.30 nests) discovered in 2002 (Olsen 2005).


Citation: BirdLife International 2012. Papasula abbotti. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 August 2014.
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