EN
Tricolored Blackbird Agelaius tricolor



Taxonomy

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- A2bc+4bc A2bc+4bc

Red List history
Year Category Criteria
2020 Endangered A2bc+4bc
2018 Endangered A2bc+3bc+4bc
2016 Endangered A2bc+3bc+4bc
2012 Endangered A2bc+3bc+4bc
2008 Endangered A2b,c; A3b,c; A4b,c
2006 Endangered
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 -
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 758,000 medium
Extent of Occurrence non-breeding (km2) 192,000 medium
Number of locations 11-100 -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals medium estimated 2017
Population trend Decreasing unknown estimated -
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) 50-79 - - -
Number of subpopulations 2-100 - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 3.98 - - -

Population justification: The global population size has been estimated at 175,000 individuals (Meese 2017), up slightly from the estimate of 145,000 individuals in 2014 (Meese 2014), indicating that the global population is considerably below 200,000 individuals.

Trend justification: Agelaius tricolor has undergone extremely rapid population declines in the past. Declines were thought to reach a maximum between 2008-2014 where statewide surveys in California (which comprises over 95% of the global population) revealed a 63% decline, equivalent to an ~86% decline across three generation lengths (12 years) (Meese 2015). However, tentative population increases have been suggested in the years since, particularly between 2014-2017 (Meese 2017, R. Meese in litt. 2020, Meehan et al. 2018) and as such, it is thought that such rapid declines may be historic. A new statewide population survey scheduled for early 2020 was postponed and as such, the population trend is retained here within the band 50-79% to reflect the recent, rapid declines but also possible recovery in the past few years.


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

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Mexico Sierra de San Pedro Mártir
Mexico Sierra Juárez
USA San Pasqual Valley - Lake Hodges
USA Santa Ana River Valley
USA Santa Clara River Valley
USA San Antonio Valley
USA Byron Area
USA Grasslands Ecological Area
USA La Grange - Waterford Grasslands
USA South Fork Kern River Valley
USA Panoche Valley
USA Sand Ridge - Tulare Lake Bed (incl. Pixley and Kern NWRs, Creighton Ranch)
USA Yolo Bypass Area
USA San Jacinto Valley
USA San Joaquin Hills
USA Edwards Air Force Base
USA Antelope Valley (Lancaster)

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Arable Land major resident
Wetlands (inland) Bogs, Marshes, Swamps, Fens, Peatlands major resident
Altitude 0 - 1300 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Agro-industry farming Timing Scope Severity Impact
Ongoing Majority (50-90%) Rapid Declines Medium Impact: 7
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Livestock farming & ranching - Agro-industry grazing, ranching or farming Timing Scope Severity Impact
Ongoing Majority (50-90%) Rapid Declines Medium Impact: 7
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Hunting & trapping terrestrial animals - Persecution/control Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) Slow, Significant Declines Past Impact
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Bubulcus ibis 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 - Unspecified species Timing Scope Severity Impact
Future Majority (50-90%) Slow, Significant Declines Low Impact: 4
Stresses
Species mortality
Pollution Agricultural & forestry effluents - Type Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation

Recommended citation
BirdLife International (2022) Species factsheet: Agelaius tricolor. Downloaded from http://www.birdlife.org on 05/07/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 05/07/2022.