<trp-post-container data-trp-post-id='360526'>Bay-ringed Tyrannulet

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En bref

  • Scientific Name: Phyllomyias zeledoni
  • Spanish Name: Mosquerito de los Andes
  • Famille : Tyrannidae
  • Known Nicknames: Bay-ringed Tyrannulet, Zeledon's Tyrannulet
  • Average Length: 11.5–12.5 cm / 4.5–4.9 in
  • Average Weight: 8–12 g / 0.28–0.42 oz
  • Envergure : N/A
  • Key Feature: Distinctive rufous-brown eye-ring and crown patch
  • Régime alimentaire principal : Principalement insectivore
  • Range: Pacific slope of Costa Rica and western Panama
  • Habitat: Subtropical montane forest canopy and edges
  • Social Structure: Solitary or in pairs, occasionally joins mixed-species flocks
  • Nesting/Breeding: Cup nest placed in a tree fork
  • Statut de conservation : Préoccupation mineure (LC)
  • Évolution démographique : Stable

The Bay-ringed Tyrannulet (*Phyllomyias zeledoni*) is a small, elusive flycatcher of Central America’s highland cloud forests, named for its most distinctive feature: a striking, rich chestnut-brown eye-ring that contrasts vividly with its otherwise subtle plumage. Its general appearance is that of a drab olive-green bird above, with a pale yellow belly and two whitish wing bars, but the warm, coppery "bay" ring encircling each eye serves as a brilliant field mark. A special feature of this species is its preference for the canopy of mossy oak and laurel trees, where it actively forages in mixed-species flocks, gleaning insects from leaves with quick, sallying movements. Despite its small size (roughly 11 cm), its sharp, whistled “tsip” call often betrays its presence before it is spotted, making it a rewarding find for birders exploring the highlands of Costa Rica and Panama.

Faits amusants

Despite its tiny size (weighing less than a AAA battery), the Bay-ringed Tyrannulet is a feisty acrobat, often seen hanging upside-down like a chickadee while gleaning insects from the undersides of leaves. It has a peculiar habit of rapidly flicking its wings and tail in a nervous, staccato motion between foraging bursts, a behavior thought to flush out hidden prey. Its most unique feature is likely its namesake—a subtle but distinct chestnut or bay-colored ring around the eye, which is surprisingly hard to spot in the dappled light of its cloud forest home. Unlike many tyrannulets that sing from exposed perches, this species is notoriously secretive, often responding to calls with a quiet, insect-like trill while staying hidden deep in the foliage.

Habitats et répartition

The Bay-ringed Tyrannulet inhabits humid montane and cloud forests, typically at elevations between 1,200 and 2,400 meters. It is most often found in the dense, mossy canopy and along forest edges, frequently associating with mixed-species foraging flocks. Its geographical range is restricted to the Pacific slope of the Andes in Costa Rica and western Panama, with isolated populations also recorded in the highlands of northern Venezuela.

Comportements & Reproduction

The Bay-ringed Tyrannulet is generally solitary or found in pairs, with no evidence of complex social structures beyond the breeding bond. Its reproductive behavior is poorly documented, but like most tyrant flycatchers, it is presumed to be monogamous during the breeding season. The species constructs a small, cup-shaped nest, often placed in a tree fork, where the female typically lays two eggs. There are no known unique reproductive strategies, though both parents likely share incubation and feeding duties, a common trait among its relatives. Mating habits have not been directly observed, but courtship likely involves vocalizations and brief aerial displays.

Alimentation

The Bay-ringed Tyrannulet primarily subsists on a diet of small arthropods and berries, gleaning insects like beetles, caterpillars, and spiders from foliage in the mid-story and canopy. An interesting aspect of its feeding behavior is its frequent participation in mixed-species foraging flocks, where it actively joins with other insectivorous birds to maximize feeding efficiency. Additionally, while it is largely insectivorous, it will seasonally supplement its diet with small fruits, particularly from mistletoes and other epiphytic berries, allowing it to adapt to variations in prey availability across its montane cloud forest habitat.

Couleurs

The Bay-ringed Tyrannulet is a small, mostly olive-green bird with a distinctive rufous or bay-colored ring encircling the eye, which is its most unique feature. It has pale yellowish underparts, two whitish wing bars, and a faint pale eyebrow stripe. This plumage provides excellent camouflage in the dappled light of its cloud forest habitat, with the olive tones blending into the foliage and the eye ring breaking up the bird’s outline.

Distribution Map

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