Guianan Tyrannulet

Fairly common by voice but inconspicuous and easily passed off as 'just another little tyrannulet'; heard far more than seen. Locally common at the right elevation along the Escalera and Gran Sabana edge.

Tiny, plain, big-headed Zimmerius with a stubby bill and longish tail; olive-green above, pale yellowish below, slightly grayer head with a grizzled face and weak pale supercilium. Narrow yellowish fringes to the wing feathers but essentially NO obvious pale wingbars (contra most other small tyrannulets). Perches fairly horizontally, often flicking/cocking the tail. Plainness + grizzled face + yellow-edged wing feathers + voice is the working ID.

Canopy and edge of humid lowland-to-foothill and lower montane forest, clearings and second growth; mostly below ~1000 m on the tepui flanks, occasionally to ~1400 m. Often associated with mistletoe (Zimmerius feed heavily on mistletoe berries).

Singles or pairs high in the canopy and at edges; gleans foliage and takes small berries, especially mistletoe; only loosely with flocks. Stays high — neck-craning views are the norm.

Dawn song a fast cricket-like couplet 'tueet, tue're'RE!...' repeated; common day call (north of the Amazon, i.e. the Venezuelan birds) a sharply downslurred double note 'chu-chup.' This call is the single best way to detect it. Trainee search term: 'Guianan Tyrannulet Zimmerius acer' on Xeno-canto / Macaulay Library; filter to Bolívar, Venezuela for the 'chu-chup' day call.

Teach this one as a VOICE bird — get clients onto the sharp 'chu-chup' day call and the cricket-like dawn song; visually it is a featureless canopy tyrannulet. IMPORTANT curriculum flag: many older lists (e.g. Hilty) label the tepui Zimmerius under 'improbus'/'Venezuelan Tyrannulet,' but current taxonomy splits that name off — the bird on the tepui slopes is Z. acer (Guianan Tyrannulet); Z. improbus (Spectacled Tyrannulet) is a NW-Venezuela/Perijá bird and Z. petersi (Venezuelan Tyrannulet) is in the Coastal Cordillera, NOT the tepuis. Use this as a taxonomy teaching moment. [Taxonomy: this is the tepui/Guianan Zimmerius (acer); distinct from Venezuelan Tyrannulet Z. petersi (coastal range) and Spectacled Tyrannulet Z. improbus (Perija/Santa Marta).]