Pterodroma axillaris

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Bibliography

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PROCELLARIIFORMES	PROCELLARIIDAE

Scientific Name:

Pterodroma axillaris

Species Authority:

(Salvin, 1893)

Common Name/s:

English

–

Chatham Island Petrel, Chatham Islands Petrel, Chatham Petrel

Assessment Information [top]

Red List Category & Criteria:

Endangered A2bde;C2a(ii) ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

Calvert, R., Butchart, S., Bird, J.

Contributor/s:

Wilson, K., Hitchmough, R., Taylor, G., Tennyson, A.

Justification:
This species has been listed as Endangered as it has a small population which has undergone very rapid declines over the past three generations. The population stabilised and has begun to increase since 2000; a trend boosted by two recent translocations.

History:

2009	–	Endangered
2008	–	Critically Endangered
2007	–	Critically Endangered
2006	–	Critically Endangered
2004	–	Critically Endangered
2000	–	Critically Endangered
1996	–	Critically Endangered
1994	–	Critically Endangered

Geographic Range [top]

Range Description:	Pterodroma axillaris is restricted to South East Island (= Rangatira) in the Chatham Islands, New Zealand, although subfossils indicate that it was once more widespread, being present on Chatham, Pitt and Mangere Islands^2,5. The earliest estimate of 50 birds was later revised to 200-400². A mark-recapture census in 2004 estimated the global population stands at 1,000-1,100 individuals comprising the 250 breeding pairs, a floater population of adults unable to breed each year owing to loss of partners or nesting sites, and juveniles aged 0-5^3,11. The increase reflects an improvement in knowledge and since 2000, a marked response to successful management with over 100 chicks now fledging annually and many recruiting back to the island. Significant declines occurred during the 20th century and continued into the 1990s; an annual decline of 1% per annum has been crudely estimated and cautious interpretation suggests a gross decline of 40-50% or more may have occurred over the past three generations¹¹. Trends appear to have stabilised since 2000, prompted by successful conservation measures. Between 2002-2006, 200 chicks were moved to a newly created predator-free site, and successful breeding occurred in 2006⁶, 2007 and 2008¹⁰. Second and third translocations are underway with 47 chicks moved to the 7.5 hectare Sweetwater Conservation Covenant on the main Chatham Island in 2008¹⁰, and 44 moved in 2009¹². It may migrate to the north Pacific Ocean like the closely-related P. nigripennis, and has been recorded at sea to the south of the islands^1,7.
Countries:	Native: New Zealand; United States
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	A mark-recapture census in 2004 estimated the global population stands at 1,000-1,100 individuals comprising 250 breeding pairs, a floater population of adults unable to breed each year owing to loss of partners or nesting sites, and juveniles aged 0 to five (G. Taylor in litt. 2009). This suggests that just 500 mature individuals are contributing to the population annually; a figure that is likely to continue increasing following two translocations.
Population Trend:	Decreasing

Population:

A mark-recapture census in 2004 estimated the global population stands at 1,000-1,100 individuals comprising 250 breeding pairs, a floater population of adults unable to breed each year owing to loss of partners or nesting sites, and juveniles aged 0 to five (G. Taylor in litt. 2009). This suggests that just 500 mature individuals are contributing to the population annually; a figure that is likely to continue increasing following two translocations.

Population Trend:

Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	It nests in burrows in very friable densely burrowed soils in lowland temperate forest and scrub, on flat to moderate sloping ground². Its diet is not well known but includes squid and small fish. Some young have returned to the island at two years old¹, and breeding has been recorded at age three, though most individuals do not breed until age five¹¹. Much of the life cycle is spent at sea; birds return to land only to breed. Visits to the colony are after dark.
Systems:	Terrestrial; Marine

Habitat and Ecology:

It nests in burrows in very friable densely burrowed soils in lowland temperate forest and scrub, on flat to moderate sloping ground². Its diet is not well known but includes squid and small fish. Some young have returned to the island at two years old¹, and breeding has been recorded at age three, though most individuals do not breed until age five¹¹. Much of the life cycle is spent at sea; birds return to land only to breed. Visits to the colony are after dark.

Systems:

Terrestrial; Marine

Threats [top]

Major Threat(s):	On South East Island intense competition for burrows with the abundant Broad-billed Prion Pachyptila vittata (including lethal attacks on chicks and eggs, and occasionally adults) is the primary threat⁸. Such competition may be the cause of the observed low breeding success and high rate of pair bond disruption. On the other islands in the group, exploitation by humans for food and introduced predators were the probable causes of extirpation³. Predator-proof fencing has facilitated translocations to two Conservation Covenants on Pitt Island and Chatham Island; alien invasive mammals will remain a constant potential threat to these sites and ongoing management will be required.

Major Threat(s):

On South East Island intense competition for burrows with the abundant Broad-billed Prion Pachyptila vittata (including lethal attacks on chicks and eggs, and occasionally adults) is the primary threat⁸. Such competition may be the cause of the observed low breeding success and high rate of pair bond disruption. On the other islands in the group, exploitation by humans for food and introduced predators were the probable causes of extirpation³. Predator-proof fencing has facilitated translocations to two Conservation Covenants on Pitt Island and Chatham Island; alien invasive mammals will remain a constant potential threat to these sites and ongoing management will be required.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway South East Island has been managed as a reserve since 1954, and cattle, sheep and goats were removed in 1961^2,3. Intensive research, ongoing since 1991, helped to identify the impact of Pachyptila vittata. As a consequence, artificial nest-sites have been provided and burrows have been blocked to prevent occupation by P. vittata during the absence of Pterodroma axillaris. P. vittata found occupying P. axillaris burrows are culled³. Since 2001, neoprene burrow flaps installed at burrow entrances have greatly reduced prion impacts during the period February to April⁹. These measures have greatly improved breeding success^3,4, from 10-30% in early 1990s to 70-80% in the past 10 years. Intensive burrow searches have now located over 160 active breeding sites of the estimated 250 pairs using the island. All newly located burrows are converted to artificial nest sites and are safe-guarded from prion interference. In 2002 a second population was created in a predator free enclosure on the 40 ha Ellen Elizabeth Preece Conservation Covenant (EEPCC). Over four years 200 chicks were transferred to this site, and by 2006 four birds had returned with a pair successfully rearing a single chick for the first time^3,6. In 2006-2007, four pairs nested and four chicks were reared. This included one pair of unbanded birds that have been lured presumably to the site by the sound attraction system. In 2008 seven chicks fledged from the EEPCC and 47 chicks were translocated to Sweetwater Conservation Covenant on Chatham Island¹⁰. Conservation Actions Proposed Monitor breeding burrows annually and band all chicks. Continue to protect nesting birds. Continue translocating birds to the Sweetwater Conservation Covenant on Chatham Island until a self-maintaining population is established. Use tiny geolocation tags to investigate the species's at-sea distribution and identify potential threats.

Conservation Actions:

Conservation Actions Underway
South East Island has been managed as a reserve since 1954, and cattle, sheep and goats were removed in 1961^2,3. Intensive research, ongoing since 1991, helped to identify the impact of Pachyptila vittata. As a consequence, artificial nest-sites have been provided and burrows have been blocked to prevent occupation by P. vittata during the absence of Pterodroma axillaris. P. vittata found occupying P. axillaris burrows are culled³. Since 2001, neoprene burrow flaps installed at burrow entrances have greatly reduced prion impacts during the period February to April⁹. These measures have greatly improved breeding success^3,4, from 10-30% in early 1990s to 70-80% in the past 10 years. Intensive burrow searches have now located over 160 active breeding sites of the estimated 250 pairs using the island. All newly located burrows are converted to artificial nest sites and are safe-guarded from prion interference. In 2002 a second population was created in a predator free enclosure on the 40 ha Ellen Elizabeth Preece Conservation Covenant (EEPCC). Over four years 200 chicks were transferred to this site, and by 2006 four birds had returned with a pair successfully rearing a single chick for the first time^3,6. In 2006-2007, four pairs nested and four chicks were reared. This included one pair of unbanded birds that have been lured presumably to the site by the sound attraction system. In 2008 seven chicks fledged from the EEPCC and 47 chicks were translocated to Sweetwater Conservation Covenant on Chatham Island¹⁰.

Conservation Actions Proposed
Monitor breeding burrows annually and band all chicks. Continue to protect nesting birds. Continue translocating birds to the Sweetwater Conservation Covenant on Chatham Island until a self-maintaining population is established. Use tiny geolocation tags to investigate the species's at-sea distribution and identify potential threats.

Bibliography [top]

	Anon. 2006. Predator control key to Chatham seabird success. World Birdwatch 28(3): 4. Heather, B. D.; Robertson, H. A. 1997. The field guide to the birds of New Zealand. Oxford University Press, Oxford, UK. Marchant, S.; Higgins, P. J. 1990. Handbook of Australian, New Zealand and Antarctic birds, 1: ratites to ducks. Oxford University Press, Melbourne. Sullivan, W., Wilson, K-J, 2001. Use of burrow flaps to minimise interference to Chatham petrel (Pterodroma axillaris) chicks by broad-billed prions (Pachyptila vittata). New Zealand Journal of Ecology 25(2): 71-75. Taylor, G. A. 2000. Action plan for seabird conservation in New Zealand. Department of Conservation, Wellington. Was, N.; Sullivan, W.; Wilson, K.-J. 2000. Burrow competition between broad-billed prions (Pachyptila vittata) and the endangered Chatham petrel (Pterodroma axillaris). Department of Conservation, Wellington.

Anon. 2006. Predator control key to Chatham seabird success. World Birdwatch 28(3): 4.

Heather, B. D.; Robertson, H. A. 1997. The field guide to the birds of New Zealand. Oxford University Press, Oxford, UK.

Marchant, S.; Higgins, P. J. 1990. Handbook of Australian, New Zealand and Antarctic birds, 1: ratites to ducks. Oxford University Press, Melbourne.

Sullivan, W., Wilson, K-J, 2001. Use of burrow flaps to minimise interference to Chatham petrel (Pterodroma axillaris) chicks by broad-billed prions (Pachyptila vittata). New Zealand Journal of Ecology 25(2): 71-75.

Taylor, G. A. 2000. Action plan for seabird conservation in New Zealand. Department of Conservation, Wellington.

Was, N.; Sullivan, W.; Wilson, K.-J. 2000. Burrow competition between broad-billed prions (Pachyptila vittata) and the endangered Chatham petrel (Pterodroma axillaris). Department of Conservation, Wellington.

Citation:	BirdLife International 2010. Pterodroma axillaris. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 22 May 2012.
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