Varied Thrush (Ixoreus naevius) - BirdLife species factsheet

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	-

Distribution

	Estimate	Data quality
Extent of Occurrence breeding/resident (km2)	6,170,000	medium
Extent of Occurrence non-breeding (km2)	4,540,000	medium
Number of locations		-
Severely Fragmented		-

Population and trend

	Value	Data quality	Derivation	Year of estimate
No. of mature individuals	35000000	poor	estimated	2019
Population trend	Decreasing		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)		-	-	-
Number of subpopulations		-	-	-
Percentage in largest subpopulation		-	-	-
Generation length (yrs)	3.31	-	-	-

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	Occurrence status	Presence	Resident	Breeding	Non-breeding	Passage
Bermuda (to UK)	V	Extant
Canada	N	Extant	Yes	Yes
Mexico	N	Extant			Yes	Yes
St Pierre and Miquelon (to France)	V	Extant
United Kingdom	V	Extant
USA	N	Extant	Yes	Yes	Yes	Yes

Important Bird and Biodiversity Areas (IBA)

Country/Territory	IBA Name
Canada	Sumallo River/Skagit Valley

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 (2022) Species factsheet: Ixoreus naevius. Downloaded from http://www.birdlife.org on 06/07/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/07/2022.