Mistletoe Tyrannulet

The Guatemalan tyrannulet, also known as the paltry tyrannulet, is a diminutive member of the tyrant flycatcher family. This avian species, with its scientific name Zimmerius vilissimus, is a dainty creature, measuring a mere 11–12 cm in length. Its plumage is a blend of olive-green across the upperparts, complemented by a subdued grey crown and grey supercilia. The wings are a darker shade, edged with yellow, and the tail is a dusky hue. The underparts present an off-white throat with grey streaking, a white belly, and flanks tinged with a subtle yellow-green. The bird's long legs are a stark blackish color.

Identification Tips

When attempting to identify the Guatemalan tyrannulet, look for its grey crown and supercilia, which contrast with the olive-green upperparts. Note the absence of wing bars, a feature that distinguishes it from some of its relatives. The bird's off-white throat with grey streaking and the yellowish feather edging on the wings are also key characteristics. Both sexes appear similar, though juveniles can be recognized by their olive crown, yellow-tinged supercilia, and broader but paler wing bars.

Habitat

This species is quite adaptable, inhabiting a range of environments from lowlands to altitudes of 2,600 m. It favors humid regions and can be found in forests, secondary growth, pastures, plantations with trees, and even shady gardens.

Distribution

The Guatemalan tyrannulet graces the skies of southern Mexico, Guatemala, El Salvador, and southern Belize with its presence.

Behaviour

An active bird, the Guatemalan tyrannulet is typically observed alone or in pairs, foraging high in the trees. It is known for its agility, making short sallies from a perch to catch its prey in flight.

Song & Calls

The vocal repertoire of this species includes a loud "peeer" call. At dawn, one might hear its plaintive "yer-de-dee, yer-de-dee" song, a melody that adds to the chorus of the forest.

Breeding

The nest of the Guatemalan tyrannulet is a marvel of avian architecture, a roughly spherical structure with a side entrance, crafted from mosses and lined with plant fiber. These nests are often situated amongst mosses, within large dead leaves, or even below the nests of yellow-olive flycatchers, at heights ranging from 2 to 15 meters above the ground. The typical clutch consists of two rufous-marked dull white eggs, incubated by the female for 14–15 days until hatching, followed by a further 17 days until the young are ready to fledge.

Diet and Feeding

The diet of this bird is primarily composed of mistletoe berries, supplemented by other berries and small insects, all of which are captured in flight.

Conservation status

The Guatemalan tyrannulet is currently classified as Least Concern by the IUCN, indicating that, for now, this species does not face any immediate threat of extinction.