Puffinus opisthomelas

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PROCELLARIIFORMES	PROCELLARIIDAE

Scientific Name:

Puffinus opisthomelas

Species Authority:

Coues, 1864

Common Name/s:

English

–

Black-vented Shearwater

Assessment Information [top]

Red List Category & Criteria:

Near Threatened ver 3.1

Year Published:

2012

Assessor/s:

BirdLife International

Reviewer/s:

Butchart, S. & Symes, A.

Contributor/s:

Howell, S. & Keitt, B.

Justification:
This species declined in the past owing to road building schemes and principally predation by introduced cats. However, these threats have ceased and the population may now begin to increase. Given the species's longevity it is retained as Near Threatened on the basis of the past declines.

History:

2010	–	Near Threatened
2008	–	Near Threatened
2005	–	Near Threatened
2004	–	Near Threatened
2000	–	Vulnerable
1996	–	Vulnerable
1994	–	Vulnerable
1988	–	Near Threatened

Geographic Range [top]

Range Description:	Puffinus opisthomelas breeds on six islands or small islets (including Guadalupe, San Benito and Natividad), off the Pacific coast of Mexico. Recent censuses have found the population to be much larger than previously thought. On Natividad, the population was estimated at 76,000 pairs in 1997 (Keitt 1998), compared with 5,000-10,000 pairs in 1991 (Everett and Anderson 1991). On San Benito, there are at least several thousand pairs (B. Tershy and B. Keitt in litt. 1999), but only 250-500 pairs were estimated in 1991 (Everett and Anderson 1991). On Guadalupe, the population was estimated at 2,500 pairs in 1991 (Everett and Anderson 1991). The current world population is estimated between 55,000 and 95,000 pairs, with the vast majority of the world's population (>95%) occurring on one island (Natividad) (B Keitt in litt. 2003). On Natividad, there was a 15% decrease in habitat and a 13-20% loss in burrows between c.1970 and the mid-1990s, and the estimated population decline was 4% per annum (Keitt 1998). Birds disperse mainly to the north reaching central California, USA, and rarely British Columbia, Canada (Carboneras 1992d).
Countries:	Native: Mexico; United States
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	The total population is around 80,000 pairs, and therefore estimated here at 160,000 mature individuals, roughly equivalent to 200,000-250,000 total individuals.
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	Breeding takes place in burrows in sandy soil and rocky crevices. Birds attend colonies for at least 10 months of the year, arriving nocturnally to reduce predation by Western Gulls Larus occidentalis (Keitt et al. 2004). Eggs are laid in March and hatching begins in early May (Keitt 1998).
Systems:	Terrestrial; Marine

Threats [top]

Major Threat(s):	On Natividad, predation by c.20 feral cats reduced the population causing >1,000 recorded deaths per month prior to their eradication which reduced mortality to less than 100 per month (Keitt et al. undated). Road construction and the establishment of a small fishing community have decreased breeding habitat and burrows (Keitt 1998), and trampled burrows and lights continue to cause some mortality (Keitt unpublished data). The Guadalupe population is thought to be predated by cats and dogs (B. Tershy and B. Keitt in litt. 1999). It is possible that cat predation has caused the extirpation, or at the very least, significantly reduced populations of this species from the main island of Guadalupe (Keitt et al. 2006). In 2003, remains were found on cliffs at the southwest edge of Guadalupe in excellent potential nesting habitat. It is not known if these observations indicate breeding or prospecting birds. The presence of habitat inaccessible to cats provides hope that this species may still breed in small remnant populations on the main island of Guadalupe (Keitt et al. 2006). Calls from prospecting adults in the cliffs of Melpomene Arroyo, indicate birds are readily available to recolonize the main island in the absence of cat predation (Keitt et al. 2006). On all islands, introduced herbivores (donkeys, goats, sheep and rabbits) have caused erosion (reducing soil for burrows), trampled burrows and destroyed vegetation, and rabbits may have displaced birds from burrows (Keitt 1998, B. Tershy and B. Keitt in litt. 1999). Gill-net fisheries may cause some mortality (Carboneras 1992d). Successful eradication of cats on Natividad has been demonstrated to dramatically lower breeding season mortality (Keitt et al. 2002).

Major Threat(s):

On Natividad, predation by c.20 feral cats reduced the population causing >1,000 recorded deaths per month prior to their eradication which reduced mortality to less than 100 per month (Keitt et al. undated). Road construction and the establishment of a small fishing community have decreased breeding habitat and burrows (Keitt 1998), and trampled burrows and lights continue to cause some mortality (Keitt unpublished data). The Guadalupe population is thought to be predated by cats and dogs (B. Tershy and B. Keitt in litt. 1999). It is possible that cat predation has caused the extirpation, or at the very least, significantly reduced populations of this species from the main island of Guadalupe (Keitt et al. 2006). In 2003, remains were found on cliffs at the southwest edge of Guadalupe in excellent potential nesting habitat. It is not known if these observations indicate breeding or prospecting birds. The presence of habitat inaccessible to cats provides hope that this species may still breed in small remnant populations on the main island of Guadalupe (Keitt et al. 2006). Calls from prospecting adults in the cliffs of Melpomene Arroyo, indicate birds are readily available to recolonize the main island in the absence of cat predation (Keitt et al. 2006). On all islands, introduced herbivores (donkeys, goats, sheep and rabbits) have caused erosion (reducing soil for burrows), trampled burrows and destroyed vegetation, and rabbits may have displaced birds from burrows (Keitt 1998, B. Tershy and B. Keitt in litt. 1999). Gill-net fisheries may cause some mortality (Carboneras 1992d). Successful eradication of cats on Natividad has been demonstrated to dramatically lower breeding season mortality (Keitt et al. 2002).

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway Natividad is a core area of the Vizcaino Biosphere Reserve, where there is some active management. In 1997-1998, goats and sheep were removed with the cooperation of the local fishing community (Keitt 1998) Cats were controlled in 1998, and eradicated by 2002 (B. Tershy and B. Keitt in litt. 1999, Keitt et al. undated). In 1998-1999, introduced herbivores were eradicated from San Benito (B. Tershy and B. Keitt in litt. 1999). Guadalupe is designated as a biosphere reserve (S. N. G. Howell in litt. 1998), but there is little active management (B. Tershy and B. Keitt in litt. 1999). Conservation Actions Proposed Monitor the population. Prohibit future road construction on Natividad and remove rubbish (B. Tershy and B. Keitt in litt. 1999). Close the middle and west San Benitos Islands to visitors (B. Tershy and B. Keitt in litt. 1999). Prevent future introductions of non-native predators and ensure all breeding islands remain cat-free (B. Tershy and B. Keitt in litt. 1999).

Conservation Actions:

Conservation Actions Underway
Natividad is a core area of the Vizcaino Biosphere Reserve, where there is some active management. In 1997-1998, goats and sheep were removed with the cooperation of the local fishing community (Keitt 1998) Cats were controlled in 1998, and eradicated by 2002 (B. Tershy and B. Keitt in litt. 1999, Keitt et al. undated). In 1998-1999, introduced herbivores were eradicated from San Benito (B. Tershy and B. Keitt in litt. 1999). Guadalupe is designated as a biosphere reserve (S. N. G. Howell in litt. 1998), but there is little active management (B. Tershy and B. Keitt in litt. 1999).

Conservation Actions Proposed
Monitor the population. Prohibit future road construction on Natividad and remove rubbish (B. Tershy and B. Keitt in litt. 1999). Close the middle and west San Benitos Islands to visitors (B. Tershy and B. Keitt in litt. 1999). Prevent future introductions of non-native predators and ensure all breeding islands remain cat-free (B. Tershy and B. Keitt in litt. 1999).

Citation:	BirdLife International 2012. Puffinus opisthomelas. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 24 May 2013.
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