Varied Thrush (Ixoreus naevius) | Details

Varied Thrush Ixoreus naevius

Current view: Data table and detailed info

Taxonomy

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: http://www.aerc.eu/DOCS/Bird_taxa_of_the_WP15.xls.
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
-	-	-

Red List history

Year	Category	Criteria
2021	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	high
Land-mass type		Average mass	-

Range

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	6,170,000 km²	medium
Extent of Occurrence (non-breeding)	4,540,000 km²	medium
Severely fragmented?	no	-

Population

	Estimate	Data quality	Derivation	Year of estimate
Population size	35000000 mature individuals	poor	estimated	2019
Population trend	decreasing	-	estimated	-
Generation length	3.31 years	-	-	-

Population justification: The global population is estimated to number 35 million mature individuals (Partners in Flight 2019).

Trend justification: The species has been undergoing a large decline at an average rate of 2.2% per year between 1970 and 2017 (Partners in Flight 2019). The population however fluctuates depending on winter conditions and trends may vary locally (Meehan et al. 2018; Pardieck et al. 2018; George 2020).

Country/territory distribution

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Bermuda (to UK)	extant	vagrant
Canada	extant	native	yes	yes
Mexico	extant	native			yes	yes
St Pierre and Miquelon (to France)	extant	vagrant
United Kingdom	extant	vagrant
USA	extant	native	yes	yes	yes	yes

Important Bird and Biodiversity Areas (IBA)

Country/Territory	IBA Name

Habitats & altitude

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Boreal	major	breeding
Forest	Temperate	major	breeding
Forest	Temperate	major	non-breeding
Altitude		Occasional altitudinal limits

Recommended citation
BirdLife International (2024) Species factsheet: Varied Thrush Ixoreus naevius. Downloaded from https://datazone.birdlife.org/species/factsheet/varied-thrush-ixoreus-naevius on 14/12/2024.
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 14/12/2024.