VU
Craveri's Murrelet Synthliboramphus craveri



Taxonomy

Taxonomic source(s)
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
- - C2a(ii)

Red List history
Year Category Criteria
2020 Vulnerable C2a(ii)
2018 Vulnerable B2ab(iii,v);C2a(ii)
2016 Vulnerable B2ab(iii,v);C2a(ii)
2012 Vulnerable B2ab(iii,v);C2a(ii)
2010 Vulnerable B2a+b(iii,v); C2a(ii)
2008 Vulnerable B2a+b(iii,v); C2a(ii)
2007 Vulnerable
2005 Vulnerable
2004 Vulnerable
2000 Vulnerable
1994 Lower Risk/Near Threatened
1988 Near Threatened
Species attributes

Migratory status not a migrant Forest dependency Does not normally occur in forest
Land mass type Land-mass type - shelf island
Average mass -
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 549,000 medium
Extent of Occurrence non-breeding (km2) 1,110,000 medium
Extent of Occurrence breeding/resident (km2) 1,700 medium
Number of locations 11-20 -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 8000 medium estimated 2015
Population trend Decreasing poor inferred -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 10-19 - - -
Decline (10 years/3 generation past and future) 10-19 - - -
Number of subpopulations 1 - - -
Percentage in largest subpopulation 100 - - -
Generation length (yrs) 5.1 - - -

Population justification: Partners in Flight (2019) estimate the population of Synthliboramphus craveri to total 8,000 mature individuals, or 12,000 individuals. Such estimates are marginally less than Gaston and Jones's (1998) older estimate of  15,000-20,000 birds and Pitman et al.'s (1995) at-sea survey estimate of c.22,000 birds, as would be expected given the moderate ongoing population declines.

Trend justification: Moderate ongoing declines are suspected owing to the various threats acting throughout the species's population.


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

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Mexico Isla San Pedro Mártir
Mexico Archipiélago Salsipuedes
Mexico Isla Rasa
Mexico Isla Tiburón-Canal Infiernillo-Estero Santa Rosa
Mexico Archipiélago Bahía de los Angeles

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Sea Cliffs and Rocky Offshore Islands major breeding
Marine Neritic Pelagic marginal resident
Marine Oceanic Epipelagic (0-200m) suitable non-breeding
Altitude 0 - 50 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Species mortality
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Unknown Unknown
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Felis catus Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Rattus rattus Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Reduced reproductive success
Pollution Agricultural & forestry effluents - Herbicides and pesticides Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) Unknown Past Impact
Stresses
Ecosystem degradation, Reduced reproductive success
Pollution Agricultural & forestry effluents - Nutrient loads Timing Scope Severity Impact
Ongoing Majority (50-90%) Unknown Unknown
Stresses
Species mortality
Pollution Industrial & military effluents - Oil spills Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Reduced reproductive success, Species mortality

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Food - human - - Non-trivial Recent

Recommended citation
BirdLife International (2022) Species factsheet: Synthliboramphus craveri. Downloaded from http://www.birdlife.org on 05/12/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 05/12/2022.