Puffinus auricularis

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:

Puffinus auricularis

Species Authority:

Townsend, 1890

Common Name/s:

English

–

Townsend's Shearwater

Assessment Information [top]

Red List Category & Criteria:

Critically Endangered B2ab(i,ii,iii,v) ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

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

Contributor/s:

Keitt, B., Martínez-Gómez, J., Tershy, B., Howell, S.

Justification:
This species has been extirpated from two islands, and breeding is now restricted to an extremely small area on one island. It qualifies as Critically Endangered because habitat is being degraded by sheep grazing, whilst feral cats are reducing numbers.

History:

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

Geographic Range [top]

Range Description:	Puffinus auricularis breeds around Cerro Evermann on Socorro in the Revillagigedo Islands, Mexico. In 1981, there were an estimated c.1,000 pairs, with more found in the north of the island in 1990. In 1993-1999, the estimate was c.500 pairs⁴ and fewer than 100 breeding pairs could be located in 2008⁷. However, 46,000 individuals (95% CI = 18,000-89,000), including 10,600 breeding birds, were estimated during at-sea censuses in 1980-1994⁵. It is clear that the breeding range has contracted, and threats indicate that numbers have declined. It formerly bred on Clarión and San Benedicto, but was almost certainly extinct on the former by 1988, and there has been no confirmed breeding on the latter since 1952. However, birds seen immediately north of San Benedicto in 1988 and 1990 provide some hope that a population remains. In the non-breeding season, it forages largely in waters over the continental shelf of Mexico⁵.
Countries:	Native: Guam; Mexico; Northern Mariana Islands; United States; United States; United States Minor Outlying Islands Vagrant: Panama Present - origin uncertain: French Southern Territories (the)
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Surveys in 2008 found fewer than 100 breeding pairs on Socorro, suggesting that even accounting for immature and non-breeding birds the total global population may be as low as 250-999 individuals, and that previous at sea estimates (which were subject to a high degree of error) may have been too large (J. Martínez-Gomez in litt. 2008).
Population Trend:	Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	On Socorro, it breeds in rocky burrows within dense bushy areas at the forest edge. Breeding is concentrated above 700 m ², but observations in 1981 suggested that the major breeding sites were at 500-650 m. Birds have been seen roosting in the naval base at Cape Rule⁴. On Clarión, it nested in burrows on grassy and bracken-covered slopes³.
Systems:	Terrestrial; Marine

Threats [top]

Major Threat(s):	Cats were introduced to Socorro in the early 1970s, and more than 92% of cat scats above 500 m contain shearwater remains⁴. Reports that rats have recently colonised Socorro are not confirmed⁴. Sheep are destroying nesting habitat across some parts of its colonies, through overgrazing and soil compaction. Pigs were introduced to Clarión soon after 1979, and by 1988 numerous shearwater remains littered burrows destroyed by severe pig rooting. Sheep (introduced in c.1990) and rabbits have also destroyed habitat and nesting sites on Clarión. In 1952, a volcanic eruption obliterated the San Benedicto population. Potential developments on Socorro including the possibility of a new federal prison could destroy breeding habitat, increase light pollution and increase the risk of accidental introduction of other invasive species⁸. Work to enlarge the airstrip in summer 2009 was believed to have caused the deaths of several birds which were attracted to lights during night-time construction works⁷. Having a distribution on relatively low-lying islands, this species is potentially susceptible to climate change through sea-level rise and shifts in suitable climatic conditions⁹.

Major Threat(s):

Cats were introduced to Socorro in the early 1970s, and more than 92% of cat scats above 500 m contain shearwater remains⁴. Reports that rats have recently colonised Socorro are not confirmed⁴. Sheep are destroying nesting habitat across some parts of its colonies, through overgrazing and soil compaction. Pigs were introduced to Clarión soon after 1979, and by 1988 numerous shearwater remains littered burrows destroyed by severe pig rooting. Sheep (introduced in c.1990) and rabbits have also destroyed habitat and nesting sites on Clarión. In 1952, a volcanic eruption obliterated the San Benedicto population. Potential developments on Socorro including the possibility of a new federal prison could destroy breeding habitat, increase light pollution and increase the risk of accidental introduction of other invasive species⁸. Work to enlarge the airstrip in summer 2009 was believed to have caused the deaths of several birds which were attracted to lights during night-time construction works⁷. Having a distribution on relatively low-lying islands, this species is potentially susceptible to climate change through sea-level rise and shifts in suitable climatic conditions⁹.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway In 1994, the Revillagigedo Islands were declared a Biosphere Reserve. There are plans to conduct surveys on Clarión and Socorro, with intensive cat-trapping taking place in 2007, but previous efforts have been poorly resourced^6,7. Pigs and sheep were eradicated from Clarión in 2002, but attempted rabbit eradication failed. The installation of an automated playback system to assist the recolonisation of Clarión is under consideration⁶. The Mexican Navy has reduced the sheep population to c.300 individuals⁸. Conservation Actions Proposed Eradicate introduced mammals on Socorro and Clarión. Determine whether a breeding population remains on San Benedicto. Assist the recolonisation of Clarión. Continue to monitor numbers on Socorro and at sea. Conduct high-level lobbying to raise awareness of the effect military operations may have on the species.

Conservation Actions:

Conservation Actions Underway
In 1994, the Revillagigedo Islands were declared a Biosphere Reserve. There are plans to conduct surveys on Clarión and Socorro, with intensive cat-trapping taking place in 2007, but previous efforts have been poorly resourced^6,7. Pigs and sheep were eradicated from Clarión in 2002, but attempted rabbit eradication failed. The installation of an automated playback system to assist the recolonisation of Clarión is under consideration⁶. The Mexican Navy has reduced the sheep population to c.300 individuals⁸.

Conservation Actions Proposed
Eradicate introduced mammals on Socorro and Clarión. Determine whether a breeding population remains on San Benedicto. Assist the recolonisation of Clarión. Continue to monitor numbers on Socorro and at sea. Conduct high-level lobbying to raise awareness of the effect military operations may have on the species.

Bibliography [top]

	AOU. 1998. Check-list of North American birds. American Ornithologists' Union, Washington, D.C. Brooke, M. De L. 2004. Albatrosses and petrels across the world. Oxford University Press, Oxford. Collar, N. J.; Gonzaga, L. P.; Krabbe, N.; Madroño Nieto, A.; Naranjo, L. G.; Parker, T. A.; Wege, D. C. 1992. Threatened birds of the Americas: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, Cambridge, U.K. Martinez-Gomez, J.E. and Jacobsen, J.K. 2004. The conservation status of Townsend's shearwater Puffinus auricularis auricularis. Biological Conservation 116(1): 35-47. Spear, L. B.; Ainley, D. G.; Nur, N.; Howell, S. N. G. 1995. Population size and factors affecting at-sea distributions of four endangered Procellariids in the tropical Pacific. Condor 97: 613-638.

AOU. 1998. Check-list of North American birds. American Ornithologists' Union, Washington, D.C.

Brooke, M. De L. 2004. Albatrosses and petrels across the world. Oxford University Press, Oxford.

Collar, N. J.; Gonzaga, L. P.; Krabbe, N.; Madroño Nieto, A.; Naranjo, L. G.; Parker, T. A.; Wege, D. C. 1992. Threatened birds of the Americas: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, Cambridge, U.K.

Martinez-Gomez, J.E. and Jacobsen, J.K. 2004. The conservation status of Townsend's shearwater Puffinus auricularis auricularis. Biological Conservation 116(1): 35-47.

Spear, L. B.; Ainley, D. G.; Nur, N.; Howell, S. N. G. 1995. Population size and factors affecting at-sea distributions of four endangered Procellariids in the tropical Pacific. Condor 97: 613-638.

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