EN
Marbled Murrelet Brachyramphus marmoratus



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
- A2bce+3bce+4bce A2bce+3bce+4bce

Red List history
Year Category Criteria
2020 Endangered A2bce+3bce+4bce
2018 Endangered A2bce+3bce+4bce
2016 Endangered A2bc+3bc+4bc
2012 Endangered A2bc+3bc+4bc
2010 Endangered A2c; A3c; A4c
2008 Endangered A2c; A3c; A4c
2005 Endangered
2004 Endangered
2000 Vulnerable
1994 Not Recognised
1988 Not Recognised
Species attributes

Migratory status not a migrant Forest dependency high
Land-mass type continent
shelf island
Average mass 220 g
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 4,790,000 km2 medium
Extent of Occurrence (non-breeding) 6,800,000 km2 medium
Number of locations 11-100 -
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 240000-280000 mature individuals medium estimated 2015
Population trend decreasing medium estimated 2002-2024
Rate of change over the past 10 years/3 generations (longer of the two periods) 50-79% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 50-79% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 50-79% - - -
Generation length 7.15 years - - -
Number of subpopulations 2-100 - - -

Population justification:

COSEWIC (2012) estimated the total population to number 358,200-417,500 individuals, rounded here to 350,000-420,000 individuals, based on 271,000 individuals in Alaska (Piatt et al. 2007), 72,600-125,600 in British Columbia (Bertram et al. 2007), and 15,400-23,900 individuals in Washington, Oregon and California (Falxa et al. 2014, Falxa and Raphael 2016). This range equates to 238,800-278,300 mature individuals, rounded here to 240,000-280,000. The latest estimate from Partners in Flight (2019) suggests a population of mature individuals of 260,000.



Trend justification: The population was estimated to have declined by c.11% in 2000-2013 in Washington, Oregon, and California (Falxa et al. 2014), with a 50% decrease in Alaska in 1972-1992 (Piatt and Naslund 1995). Although population declines in Oregon and California are reported to have been stabilising in recent years (Falxa and Raphael 2016, A. Burger in litt. 2020), declines have continued in Washington State with adult Murrelet densities declining on the shores of the San Juan Islands from 11.16 to 5.76 individuals/km2 between 1995-2012, mirroring declines witnessed by large-scale at-sea surveys (Lorenz and Raphael 2018). Population declines in Washington are currently estimated at ~4.6% per year (Falxa and Raphael 2016). At-sea surveys over the past 25 years in British Columbia suggest declines of c.1% per year (Piatt et al. 2006), although radar surveys suggest the population may have been relatively stable since 1999 with declines in some regions of British Columbia (COSEWIC 2012, Bertram et al. 2015). Availability of nesting habitat in British Columbia, which is strongly correlated with local breeding populations (Burger 2001, Burger et al. 2004), has declined by 22% between 1978 and 2008, and is continuing (COSEWIC 2012). Overall declines are suspected to be very rapid and on-going due to very low measured productivity rates.


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

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Canada Barkley Sound
Canada Cleland Island and Southeast Clayoquot Sound
Canada Desolation Sound
Canada Nootka Island banks
USA Ano Nuevo Area
USA Cape Blanco Nearshore Ocean
USA Cape Meares Marbled Murrelet
USA Central CA MAMU
USA Del Norte Coast
USA Glacier Bay & Icy Strait
USA Half Moon Bay, CA MAMU
USA Humboldt Bay
USA Humboldt Lagoons
USA Icy Bay
USA Kachemak Bay
USA Klamath, CA MAMU
USA Marbled Murrelet IBA
USA North Olympic Marbled Murrelet
USA Olympic Coast Marbled Murrelet
USA Olympic Continental Shelf
USA Pelican Bay, CA MAMU
USA Point No Point
USA Port Angeles Marbled Murrelet
USA Port Snettisham
USA Prince William Sound
USA Samish/Padilla Bays
USA Skagit Bay
USA Stephens Passage & Tracy-Endicott Arms
USA Uganik Bay & Viekoda Bay

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Temperate major breeding
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes suitable non-breeding
Marine Neritic Pelagic suitable resident
Marine Oceanic Epipelagic (0-200m) suitable non-breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) major non-breeding
Wetlands (inland) Permanent Freshwater Marshes/Pools (under 8ha) major non-breeding
Altitude   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%) Slow, Significant Declines Medium Impact: 6
Stresses
Indirect ecosystem effects, Reduced reproductive success, Species mortality
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Very Rapid Declines High Impact: 8
Stresses
Ecosystem degradation, Reduced reproductive success
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Indirect ecosystem effects, Reduced reproductive success
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Indirect ecosystem effects, Reduced reproductive success
Human intrusions & disturbance Work & other activities Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species disturbance, Reduced reproductive success
Invasive and other problematic species, genes & diseases Problematic native species/diseases Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Reduced reproductive success
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

Recommended citation
BirdLife International (2024) Species factsheet: Marbled Murrelet Brachyramphus marmoratus. Downloaded from https://datazone.birdlife.org/species/factsheet/marbled-murrelet-brachyramphus-marmoratus on 24/12/2024.
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 24/12/2024.