NT
Cassin's Auklet Ptychoramphus aleuticus



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
2020 Near Threatened A2abce+3bce+4abce
2018 Near Threatened A2b+3b+4b
2016 Near Threatened A2b+3b+4b
2015 Near Threatened A2b+3b+4b
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) 8,620,000 km2 medium
Extent of Occurrence (non-breeding) 12,100,000 km2 medium
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 3600000 mature individuals poor estimated 2009
Population trend decreasing - estimated 2003-2024
Rate of change over the past 10 years/3 generations (longer of the two periods) 20-29% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 20-29% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 20-29% - - -
Generation length 6.94 years - - -

Population justification: The total population is estimated to be at least 3,600,000 breeding birds (Nettleship 1996), which equates to approximately 5,400,000 individuals.

Trend justification: In North America, this species has undergone a large and statistically significant decrease over the last 40 years (Butcher and Niven 2007). A study by Rodway and Lemon (2011) found declines in monitored burrows at several colonies in British Columbia and estimated a 40% decline in monitored burrows over 20 years between 1989 and 2009 in the largest known breeding population on Triangle Island (part of the Scott Islands). Declines appear to have begun in c.1990. If the declines on Triangle Island are representative of the whole Scott Islands population, there could have been a total loss of approximately 800,000 birds in the region, or >20% of the world breeding population. Large-scale declines have also been documented on the South Farallon Islands, California (H. Carter in litt. 2013) whilst the Christmas Bird Count currently estimates USA-wide declines at rates of ~1.42% per year, or ~25.75% across three generations (Meehan et al. 2018). The overall rate of decline is currently placed in the band 20-29% in three generations, but confirmation that declines similar to those seen at Triangle Island, British Colombia and the South Farallon Islands, California are taking place across the whole range would lead to the overall rate of decline being increased.


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Canada extant native yes yes yes
Mexico extant native yes yes
USA extant native yes yes yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Canada Anthony Island
Canada Englefield Bay Islands
Canada Frederick Island
Canada Hippa Island
Canada Kerouard and St. James Islands
Canada Moore and Byers Islands and Banks
Canada Ramsay and Northern Juan Perez Sound Islands
Canada Rankine and Langtry Islands
Canada Scott Island Group
Canada Skincuttle Inlet Islands
Canada Solander Island and Brooks Bay
Mexico Bahía Todos Santos
Mexico Isla Asunción
Mexico Isla San Roque
Mexico Islas San Benito
USA Amagat & Umga Island Colonies
USA Castle Rock Colonies
USA Cherni Island Complex Colonies
USA Forrester Island Colonies
USA Gulf of Alaska Shelf 155W57N
USA Olympic Continental Shelf

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Sea Cliffs and Rocky Offshore Islands 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 - 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: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Species mortality
Climate change & severe weather Temperature extremes Timing Scope Severity Impact
Ongoing Majority (50-90%) Causing/Could cause fluctuations Medium Impact: 6
Stresses
Indirect ecosystem effects, Reduced reproductive success, Species mortality
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species disturbance, Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Capra hircus Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species disturbance, Ecosystem degradation, 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
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Oryctolagus cuniculus Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Ecosystem degradation, Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Procyon lotor Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Rattus norvegicus 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
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Vulpes vulpes Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Falco peregrinus Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Haliaeetus leucocephalus Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Larus occidentalis Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species mortality
Pollution Excess energy - Light pollution Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
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 Scale
Food - human subsistence, national

Recommended citation
BirdLife International (2024) Species factsheet: Cassin's Auklet Ptychoramphus aleuticus. Downloaded from https://datazone.birdlife.org/species/factsheet/cassins-auklet-ptychoramphus-aleuticus on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/12/2024.