Mountain Tyrannulet (Zimmerius improbus) - BirdLife species factsheet

Mountain Tyrannulet Zimmerius improbus

Current view: Data table and detailed info

Taxonomy

Taxonomic note
Zimmerius improbus and Z. petersi (del Hoyo and Collar 2016) were previously lumped as Z. improbus following Sibley and 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.

IUCN Red list criteria met and history

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2016	Least Concern

Species attributes

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

Extent of occurrence (EOO)

	Estimate	Data quality
Extent of Occurrence breeding/resident (km2)	116,000	medium
Number of locations		-
Fragmentation		-

Population and trend

	Estimate	Data quality	Derivation	Year of estimate
No. of mature individuals	unknown	not applicable	not applicable	0
Population trend	Decreasing		suspected	-
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		-	-	-
Largest subpopulations		-	-	-
Generation length (yrs)	3.6	-	-	-

Population justification: The global population size has not been quantified, but prior to being split from Z. petersi the species was described as uncommon to common (del Hoyo et al. 2004).

Trend justification: Deforestation has been severe in parts of this species's range (del Hoyo et al. 2004), thus the population is suspected to be in decline.

Country/territory distribution

Country/Territory	Occurrence status	Presence	Resident	Breeding	Non-breeding	Passage
Colombia	N	Extant	Yes
Venezuela	N	Extant	Yes

Important Bird and Biodiversity Areas (IBA)

Country/Territory	IBA Name

Habitats & altitude

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	suitable	resident
Forest	Subtropical/Tropical Moist Montane	major	resident
Altitude	400 - 3000 m	Occasional altitudinal limits

Recommended citation
BirdLife International (2019) Species factsheet: Zimmerius improbus. Downloaded from http://www.birdlife.org on 23/09/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/09/2019.