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Ardenna bulleri

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA AVES PROCELLARIIFORMES PROCELLARIIDAE

Scientific Name: Ardenna bulleri
Species Authority: (Salvin, 1888)
Common Name(s):
English Buller's Shearwater
Synonym(s):
Ardenna bulleri bulleri Christidis and Boles (2008)
Puffinus bulleri Salvin, 1888
Taxonomic Notes: Ardenna bulleri (del Hoyo and Collar 2014) was previously placed in the genus Puffinus.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Szabo, M. & Taylor, G.
Facilitator/Compiler(s): Benstead, P., Calvert, R., Mahood, S., McClellan, R. & Taylor, J.
Justification:
This species qualifies as Vulnerable because the population is restricted to a very small area when breeding, and remains at risk from the accidental introduction of predators and other catastrophes. If it succeeds in expanding its range, it may be downlisted to Near Threatened.

Geographic Range [top]

Range Description: Ardenna bulleri breeds only at the Poor Knights Islands, New Zealand. The species is restricted to two main islands, Aorangi and Tawhiti Rahi, and five other islets and stacks (Marchant and Higgins 1990). In the 1980s, one pair was found breeding on the Simmonds Islands, in the far north of New Zealand (Taylor 2000). Between 1938 and 1981, the population on Aorangi increased from c.200 to c.200,000 pairs (Harper 1983, Heather and Robertson 1997). However, surveys in 2011 suggested that there were fewer than 200,000 burrows, and perhaps only c.50,000 (G. Taylor in litt. 2012). In 2011, breeding success on Aorangi Island was noted to be very low, with only 16 chicks found in the 150 burrows sampled (G. Taylor in litt. 2012). The total population has been estimated at 2.5 million birds (Marchant and Higgins 1990), although this now regarded as too high (G. Taylor in litt. 2012). It migrates to the northern Pacific Ocean, from Japan to North America and east to California, and is occasionally found off South America (Heather and Robertson 1997, Taylor 2000).

Countries:
Native:
American Samoa (American Samoa); Australia; Canada; Chile; Cook Islands; French Polynesia; Marshall Islands; Mexico; New Caledonia; New Zealand; Niue; Norfolk Island; Peru; Russian Federation; United States; United States Minor Outlying Islands; Wallis and Futuna
Vagrant:
Fiji; Japan
Present - origin uncertain:
Costa Rica; Ecuador; French Southern Territories; Kiribati; Micronesia, Federated States of ; Nauru; Samoa; Solomon Islands; Tokelau; Tonga; Tuvalu; Vanuatu
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The total population is estimated at 2.5 million birds (Marchant and Higgins 1990), although this is now likely to be too high (G. Taylor in litt. 2012).

Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: It nests in burrows or on rock-crevices and ledges, often under dense vegetation. It feeds on krill, small fish, salps and jellyfish (Marchant and Higgins 1990, Heather and Robertson 1997).

Systems: Terrestrial; Marine

Threats [top]

Major Threat(s): It was previously caught in north Pacific drift-nets (Gould et al. 1998), and is still potentially at risk from set-nets. It may be caught on longlines, in trawling operations and on hand and reel lines, but little documented evidence is available (Taylor 2000). Domestic pigs were previously a threat (removed in 1936), and the species would be at risk of mammalian predators if introduced. The species is potentially threatened by climate change because it has a geographically bounded distribution: it is restricted to an island or islands with a maximum altitude of 218 m (BirdLife International, unpublished data). Poor breeding success recorded on Aorangi Island in 2011 may have been related to a strong La Niña climate pattern in 2010-2011, but data from some birds fitted with geolocators indicated that incubation shifts were around twice the length of those published in the 1980s (G. Taylor in litt. 2012). There has been intensive purse-seine fishing of pelagic fish in the Hauraki Gulf in recent decades, which may have impacted the species through food resource depletion, as it is known to feed in these areas and, perhaps connected to this, populations of Red-billed Gulls Larus scopulinus on the Mokohinau Islands have crashed from c.20,000 birds in the 1960s to fewer than 500 birds in 2011 (G. Taylor in litt. 2011). Further investigation is required.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The eradication of pigs from Aorangi in 1936 caused a massive increase in the population, with the recolonisation probably coming from the nearby predator-free island, Tawhiti Rahi (Heather and Robertson 1997). Fishing has been banned at the Poor Knights Islands Marine Reserve since 1996 and entry onto the island reserve is prohibited (Szabo in litt. 2004). The International Maritime Organisation (IMO) established the world's first mandatory "area to be avoided" (ATBA) for large shipping vessels, including oil tankers, around the islands in 2004 (Szabo in litt. 2004). Breeding islands have permanent poisoned bait stations and each island is checked every year for any evidence that rodents have arrived (G. Taylor in litt. 2012). The species has been the subject of tracking studies utilising geolocators, with further data collection planned for 2013 (G. Taylor in litt. 2012).

Conservation Actions Proposed
Complete an accurate population census (including on Aorangi Island, to better assess breeding numbers [G. Taylor in litt. 2012]), assess the current status of breeding on Simmonds Islands and identify any signs of prospecting on other island groups. Establish monitoring plots on Poor Knights to determine the rate and pattern of colony expansion (Taylor 2000). Quantify the impact of bycatch during fishing activities. If judged necessary, work with fisheries to develop bycatch reduction measures.


Citation: BirdLife International 2012. Ardenna bulleri. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 19 December 2014.
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