• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic note

Molothrus aeneus and M. armenti (del Hoyo and Collar 2016) were previously lumped as M. aeneus following AOU (1998 & supplements); SACC (2005 & updates); Sibley & Monroe (1990, 1993).

 

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.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2021	Near Threatened	A2c+3c+4c; B1ab(ii,iii,v); C1+2a(ii)
2016	Vulnerable	C2a(ii)
2012	Not Recognised
2008	Not Recognised
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Threatened

Migratory status	not a migrant	Forest dependency	low
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	13,300 km2	medium
Number of locations	11-100	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	2500-9999 mature individuals	poor	suspected	2020
Population trend	decreasing	-	suspected	2015-2025
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	2.5 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: The population size has not been quantified directly, but the species is described as rare to common in suitable habitat (Renjifo et al. 2016). Nevertheless, assuming that not all of its range is inhabited, the population is suspected to not exceed 10,000 mature individuals; it is therefore here placed in the band 2,500-9,999 mature individuals. It is further assumed that all individuals belong to the same subpopulation. Based on its good dispersal abilities, ability to tolerate a variety of habitats, and the continuous records within the range (Renjifo et al. 2016; eBird 2021), it is assumed that all individuals belong to the same subpopulation.

Trend justification: Deforestation and land clearance has affected the species's range. Short-term trends quantify the rate of habitat loss as 23% over ten years between 2001 and 2011 (Renjifo et al. 2016). Since the species does inhabit disturbed habitats such as roadsides, population declines may be moderate; assuming that habitat loss is continuing at the same rate to the present day and into the future, the rate of population decline is precautionarily suspected at 20-29% over ten years.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Colombia	extant	native	yes

Country/Territory	IBA Name

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Arable Land	suitable	resident
Artificial/Terrestrial	Pastureland	suitable	resident
Artificial/Terrestrial	Rural Gardens	suitable	resident
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Dry	suitable	resident
Altitude	0 - 200 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Agro-industry farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Wood & pulp plantations - Agro-industry plantations	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Residential & commercial development	Housing & urban areas	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem conversion

Purpose	Scale
Pets/display animals, horticulture	international

---

Recommended citation
BirdLife International (2024) Species factsheet: Bronze-brown Cowbird Molothrus armenti. Downloaded from https://datazone.birdlife.org/species/factsheet/bronze-brown-cowbird-molothrus-armenti on 22/11/2024.
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 22/11/2024.