NT
Black-vented Shearwater Puffinus opisthomelas



Taxonomy

Taxonomic source(s)
Brooke, M. de L. 2004. Albatrosses and Petrels Across the World. Oxford University Press, Oxford.
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - D2

Red List history
Year Category Criteria
2016 Near Threatened A2ce; B2ab(i,ii,iii,v)
2012 Near Threatened A2ce;B2ab(i,ii,iii,v)
2010 Near Threatened A2c,e; B2a+b(i,ii,iii,v)
2008 Near Threatened A2c,e; B2a+b(i,ii,iii,v)
2005 Near Threatened
2004 Near Threatened
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Near Threatened
Species attributes

Migratory status full migrant Forest dependency Does not normally occur in forest
Land mass type Land-mass type - shelf island
Average mass 408 g
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 2,460,000 medium
Extent of Occurrence breeding/resident (km2) 280 medium
Number of locations 4 -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 82000 medium estimated 2004
Population trend Unknown poor -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Largest subpopulations - - -
Generation length (yrs) 18.3 - - -

Population justification: The total population estimated in 1998-1999 was around 80,000 pairs, and therefore 160,000 mature individuals. In 2016, aerial photography and GIS were used to count during the breeding season the total number of occupied and unoccupied burrows in Natividad Island. The counts gave a figure of 37,858 (±8510 SE) breeding pairs, and therefore about 75,600 individuals. This figure was based on the initial occupancy of burrows on February 2016. Of the initial number of occupied burrows, there were 4,543 (about 12% of the burrows occupied) which were initially occupied but later abandoned by the birds (Albores-Barajas et al. in press).

Counts produced much lower numbers than previous estimates. It is likely that the methods used in 1998-99 overestimated the population size. The author extrapolated counts of nests in selected areas to the whole surface of the island used by birds without considering that there were large areas without any burrow. During the last survey, thanks to aerial photography, it was possible to precisely count all the burrows which were actually present (Albores-Barajas et al. in press). The total number of burrows counted, including occupied and abandoned burrows, was 56,395 with a relatively low occupancy (between 75% and 50% depending on the area).

Between 2014 and early 2016 the birds on Natividad were also affected by the presence of a wire fence next to the local rubbish dump and on the trajectory used by bird when moving from colony to sea. Several carcasses were found during the survey in February 2016. When the situation was analysed using thermal cameras, it was observed that at least 20 individuals collided with the fence every day, resulting in seven dead individuals/day. This mortality rate was estimated equivalent to the predation of five cats (Albores-Barajas et al. in press). The fence was immediately removed after the observations when it was communicated to the local community and to the Biosphere Reserve.

Trend justification: The species declined dramatically owing to predation, in particular by introduced cats. However, eradication of these from its principal breeding island, Natividad, suggests that immediate threats to the species have now been significantly reduced and recruitment to the population may increase. Nevertheless, the current trend still remain unknown. Although the counts from 2016 are much lowers than in 1998-1999, data from 1998-1999 has overestimated the population and thus, the data doesn't seem to be comparable. Bycatch in fisheries remains a threat but its impacts are unknown.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Mexico N Extant Yes
USA N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Mexico Isla Benitos
Mexico Isla Guadalupe
Mexico Island Natividad

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Caves and Subterranean Habitats (non-aquatic) Caves suitable breeding
Marine Neritic Macroalgal/Kelp suitable breeding
Marine Neritic Macroalgal/Kelp suitable non-breeding
Marine Neritic Pelagic major breeding
Marine Neritic Pelagic major non-breeding
Marine Neritic Seagrass (Submerged) suitable breeding
Marine Neritic Seagrass (Submerged) suitable non-breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel suitable breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel suitable non-breeding
Marine Neritic Subtidal Rock and Rocky Reefs suitable breeding
Marine Neritic Subtidal Rock and Rocky Reefs suitable non-breeding
Marine Neritic Subtidal Sandy suitable breeding
Marine Neritic Subtidal Sandy suitable non-breeding
Marine Neritic Subtidal Sandy-Mud suitable breeding
Marine Neritic Subtidal Sandy-Mud suitable non-breeding
Marine Oceanic Epipelagic (0-200m) major breeding
Marine Oceanic Epipelagic (0-200m) major non-breeding
Marine Oceanic Mesopelagic (200-1000m) major breeding
Marine Oceanic Mesopelagic (200-1000m) major non-breeding
Shrubland Subtropical/Tropical Moist major breeding
Altitude 0 - 100 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Whole (>90%) Slow, Significant Declines Medium Impact: 7
Stresses
Species mortality
Human intrusions & disturbance Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species - Canis familiaris Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species - Capra hircus Timing Scope Severity Impact
Past, Unlikely to Return Whole (>90%) Slow, Significant Declines Past Impact
Stresses
Ecosystem degradation
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species - Equus asinus Timing Scope Severity Impact
Past, Unlikely to Return Whole (>90%) Slow, Significant Declines Past Impact
Stresses
Ecosystem degradation
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species - Felis catus Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species - Oryctolagus cuniculus Timing Scope Severity Impact
Past, Unlikely to Return Whole (>90%) Slow, Significant Declines Past Impact
Stresses
Ecosystem degradation
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species - Ovis aries Timing Scope Severity Impact
Past, Unlikely to Return Whole (>90%) Slow, Significant Declines Past Impact
Stresses
Ecosystem degradation
Pollution Excess energy - Light pollution Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species mortality
Residential & commercial development Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Transportation & service corridors Timing Scope Severity Impact
Past, Likely to Return Minority (<50%) Slow, Significant Declines Past Impact
Stresses
Ecosystem degradation, Ecosystem conversion

Recommended citation
BirdLife International (2017) Species factsheet: Puffinus opisthomelas. Downloaded from http://www.birdlife.org on 24/11/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 24/11/2017.