LC
Mountain Tyrannulet Zimmerius improbus



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
2022 Least Concern
2016 Least Concern
Species attributes

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

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 116,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals unknown not applicable not applicable 0
Population trend Stable 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 - - -
Percentage in largest subpopulation - - -

Population justification: The global population size has not been quantified given recent taxonomic splits. Prior to being split, the species has been described as uncommon to common (del Hoyo et al. 2004).

Trend justification: The population trend has not been investigated. Tree cover loss within the range is very low (<2% over ten years; Global Forest Watch 2021, using Hansen et al. [2013] data and methods disclosed therein). Given the species' apparent tolerance of some habitat degradation and open habitats (Jones 2020), deforestation is unlikely to drive a population decline. Therefore, in the absence of evidence for any substantial threats, the population is suspected to be stable.


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
Colombia Cuchilla de San Lorenzo
Colombia Cerro Pintado (Serranía de Perijá)
Venezuela Parque Nacional El Tamá
Venezuela Parque Nacional Sierra Nevada
Venezuela Parque Nacional Sierra La Culata
Venezuela Parque Nacional Guaramacal
Venezuela Parque Nacional Páramos Batallón y La Negra and surrounding areas

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 (2023) Species factsheet: Zimmerius improbus. Downloaded from http://www.birdlife.org on 28/03/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 28/03/2023.