Family Tyrant-flycatchers (Tyrannidae)

Least Concern

Mountain Tyrannulet (Zimmerius improbus)


French: Tyranneau trompeur German: Küstenkordilleren-Kleintyrann Spanish: Mosquerito serrano
Other common names: Specious Tyrannulet

Tyranniscus improbus

P. L. Sclater and Salvin

, 1871,

Mérida, Venezuela


Previously considered conspecific with Z. vilissimus, but differs in plumage, voice and habitat. Until recently also considered conspecific with Z. petersi (which see). Geographical delimitation of races may be in need of revision#R. Two subspecies recognized.

Subspecies and Distribution
  • Z. i. tamae (Phelps, Sr & Phelps, Jr, 1954) – N Colombia (Santa Marta Mts) and W Venezuela (Sierra de Perijá and Páramo de Tamá, in Táchira).
  • Z. i. improbus (P. L. Sclater & Salvin, 1871) – N Colombia (Norte de Santander) and NW Venezuela (Táchira, Mérida, Barinas, Trujillo).
  • Descriptive notes

    11·5–12·7 cm; 10·9 g. Nominate race has sharply defined, curved white supercilium contrasting with brown immediately anterior to eye, white partial... read more


    Distinctive, loud series of 3–4 sad-sounding, slightly descending whistled notes, each... read more


    Humid montane forest, forest borders, and tall second growth with clearings; mainly 1200–2500... read more

    Food and feeding

    Insects, also regularly mistletoe (Loranthaceae) and other small berries. Forages singly or in pairs, often following mixed-species flocks... read more


    Birds in breeding condition in Mar–Nov in Venezuela (Sierra de Perijá) and N end of E Andes in Colombia. Reported to construct... read more



    Status and conservation

    Not globally threatened (Least Concern). Uncommon to common. Known from several protected areas throughout range including Sierra Nevada National Park (Venezuela). Although... read more

    Recommended citation

    Fitzpatrick, J., Christie, D.A. & Kirwan, G.M. (2020). Mountain Tyrannulet (Zimmerius improbus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 19 January 2020).