Western Grebe Aechmophorus occidentalis


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
2019 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 full migrant Forest dependency Does not normally occur in forest
Land mass type Average mass -

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 8,380,000 medium
Extent of Occurrence non-breeding (km2) 3,220,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 80000-90000 poor estimated 2011
Population trend Stable 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) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 8 - - -

Population justification: The population is estimated to number 120,000-130,000 individuals (Wetlands International 2018). This roughly equates to 80,000-90,000 mature individuals.

Trend justification: Data from the North American Breeding Bird Survey, combined for Aechmophorus occidentalis and A. clarkii, implies that the species has undergone a non-significant increase over the past three generations (24 years) (Sauer et al. 2017); whereas in Wetlands International (2018) the population trend is unknown. Given the uncertainty, and the fact that trend data is for these two species combined, the species is tentatively placed here as stable.

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

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Canada Lake Newell and Kitsim Reservoir
Canada McGregor Lake and Travers Reservoir
Canada Whitford and Rush Lakes
Canada Muriel Lake
Canada Utikuma and Utikumasis Lakes
Canada Cardinal Lake
Canada Peace-Athabasca Delta
Canada Lesser Slave Lake PP
Canada Pakowki Lake
Canada Eagle, Namaka and Stobart Lakes
Canada Frank Lake (south)
Canada Lac La Biche
Canada Boundary Bay - Roberts Bank - Sturgeon Bank (Fraser River Estuary)
Canada English Bay and Burrard Inlet
Canada Jervis Inlet/McRae Islet
Canada Cowichan estuary
Canada Little Qualicum Estuary to Nanoose Bay
Canada Baynes Sound
Canada Barkley Sound
Canada Delta Marsh
Canada Kaweenakumik Lake
Canada Netley-Libau Marsh
Canada Oak Lake/Plum Lakes Area
Canada North, West, and East Shoal Lakes
Canada Marshy Point
Canada Sandy Bay Marshes
Canada Fife Lake
Canada Old Wives-Frederick Lakes
Canada East Lake Diefenbaker
Canada Paysen/Kettlehut Lake
Canada Pelican Lake
Canada Blackstrap Coulee
USA Bear River Bay UT02
Mexico Bahía Todos Santos
Mexico Complejo de Presas de Río Fuerte
Mexico Delta del Río Colorado

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Aquatic & Marine Artificial/Aquatic - Water Storage Areas (over 8ha) suitable breeding
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes suitable breeding
Marine Neritic Estuaries suitable non-breeding
Marine Neritic Pelagic suitable non-breeding
Wetlands (inland) Bogs, Marshes, Swamps, Fens, Peatlands suitable breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) major breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) major non-breeding
Wetlands (inland) Permanent Saline, Brackish or Alkaline Marshes/Pools suitable non-breeding
Altitude 0 - 2500 m Occasional altitudinal limits  

Recommended citation
BirdLife International (2023) Species factsheet: Aechmophorus occidentalis. Downloaded from on 27/03/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 27/03/2023.