LC
Rhinoceros Auklet Cerorhinca monocerata



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
- - -

Red List history
Year Category Criteria
2018 Least Concern
2016 Least Concern
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

Migratory status not a migrant Forest dependency does not normally occur in forest
Land-mass type Average mass -
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 18,400,000 km2 medium
Extent of Occurrence (non-breeding) 30,100,000 km2 medium
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size unknown poor estimated 1996
Population trend decreasing - suspected -
Generation length 8 years - - -

Population justification: The global population is estimated to number > c.1,300,000 individuals (del Hoyo et al. 1996), while national population estimates include: < c.1,000 wintering individuals in Korea; c.10,000-1 million breeding pairs c.1,000-10,000 wintering individuals in Japan and c.10,000-100,000 breeding pairs in Russia (Brazil 2009).

Trend justification: The population is suspected to be in decline owing to bycatch, predation by invasive species and climate change.


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Canada extant native yes
China (mainland) extant native yes
Japan extant native yes
Mexico extant native yes
North Korea extant native yes
Russia extant native yes
Russia (Asian) extant native yes
South Korea extant native yes
USA extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Canada Anthony Island
Canada Duke of Edinburgh Ecological Reserve
Canada Englefield Bay Islands
Canada Lucy Islands
Canada Moore and Byers Islands and Banks
Canada Scott Island Group
Japan Eastern Hokkaido - Marine
Japan Matsumae islets
Japan Northern Hokkaido - Marine
Japan Sanriku coast and Matsumaekojima - Marine
Japan Teuri island
Japan Yururi and Moyururi islets
Russia (Asian) Kuril islands (between Urup and Paramushir)
Russia (Asian) Lesser Kuril Ridge and Kunashir Island
Russia (Asian) Tyuleniy Island
USA Forrester Island Colonies
USA Olympic Continental Shelf
USA Outer Islands Marine

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Grassland Temperate major breeding
Marine Neritic Macroalgal/Kelp major resident
Marine Neritic Pelagic major resident
Marine Neritic Seagrass (Submerged) major resident
Marine Neritic Subtidal Loose Rock/pebble/gravel major resident
Marine Neritic Subtidal Rock and Rocky Reefs major resident
Marine Neritic Subtidal Sandy major resident
Marine Neritic Subtidal Sandy-Mud major resident
Marine Oceanic Epipelagic (0-200m) suitable resident
Marine Oceanic Mesopelagic (200-1000m) suitable resident
Altitude 0 - 200 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%) Slow, Significant Declines Low Impact: 5
Stresses
Species mortality
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Indirect ecosystem effects, Ecosystem degradation, Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species disturbance, Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Procyon lotor Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species disturbance, Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Vulpes lagopus Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Indirect ecosystem effects, Reduced reproductive success, Species mortality
Pollution Industrial & military effluents - Oil spills Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Reduced reproductive success

Utilisation
Purpose Scale
Food - human subsistence, national
Pets/display animals, horticulture international

Recommended citation
BirdLife International (2025) Species factsheet: Rhinoceros Auklet Cerorhinca monocerata. Downloaded from https://datazone.birdlife.org/species/factsheet/rhinoceros-auklet-cerorhinca-monocerata on 12/01/2025.
Recommended citation for factsheets for more than one species: BirdLife International (2025) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 12/01/2025.