EN
Guadalupe Murrelet Synthliboramphus hypoleucus



Taxonomy

Taxonomic note
Synthliboramphus hypoleucus and S. scrippsi (del Hoyo and Collar 2014) were previously lumped as S. hypoleucus following Sibley and Monroe (1990, 1993).

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
- B2ab(iv,v) B2ab(iv,v)

Red List history
Year Category Criteria
2018 Endangered B2ab(iv,v)
2016 Endangered B2ab(iv,v)
2014 Endangered B2ab(iv,v)
Species attributes

Migratory status not a migrant Forest dependency Does not normally occur in forest
Land mass type Average mass 167 g
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 469,000 medium
Extent of Occurrence non-breeding (km2) 1,760,000 medium
Extent of Occurrence breeding/resident (km2) 340 medium
Number of locations 2-5 -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 5000 medium estimated 2012
Population trend Decreasing poor suspected -
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) 12.1 - - -

Population justification: It is estimated to number fewer than 5,000 breeding birds (Birt et al. 2012), which are presumed to form one sub-population. Until further data are obtained, an estimate of 5,000 mature individuals is used in this assessment, which is assumed here to equate to c.7,500 individuals in total.

Trend justification: A number of colonies have been extirpated by introduced predators and alien invasive species continue to threaten some colonies. A number of other threatening processes are on-going, the combined effects of which are suspected to be causing a moderate decline in this species's global population.


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

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Mexico Isla Asunción
Mexico Isla Natividad
Mexico Isla Guadalupe
USA Channel Islands - Northern

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Sea Cliffs and Rocky Offshore Islands major breeding
Marine Neritic Pelagic major resident
Marine Oceanic Epipelagic (0-200m) suitable resident
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 Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species mortality
Climate change & severe weather Temperature extremes Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Indirect ecosystem effects, Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Felis catus Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant 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 Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Reduced reproductive success, Species mortality
Pollution Industrial & military effluents - Oil spills Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species mortality
Pollution Industrial & military effluents - Type Unknown/Unrecorded Timing Scope Severity Impact
Past, Unlikely to Return Unknown Unknown Past Impact
Stresses
Reduced reproductive success, Species mortality

Recommended citation
BirdLife International (2021) Species factsheet: Synthliboramphus hypoleucus. Downloaded from http://www.birdlife.org on 25/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/10/2021.