<trp-post-container data-trp-post-id='363222'>Southern Bristle-Tyrant

En bref

• Scientific Name: Phylloscartes eximius
• Spanish Name: Tirano barbudo sureño
• Famille : Tyrannidae
• Known Nicknames: Southern Bristle Tyrant
• Longueur moyenne : 11–12 cm / 4,3–4,7 pouces
• Average Weight: 8–10 g / 0.28–0.35 oz
• Envergure : N/A
• Key Feature: Long, bristle-like feathers around the bill
• Régime alimentaire principal : Insectivore
• Range: Southeastern Brazil, eastern Paraguay, and northeastern Argentina
• Habitat: Humid montane and lowland forests, forest edges
• Structure sociale : Solitaires ou en couples
• Nidification/Reproduction : Nid en forme de coupe situé dans une fourche d'arbre ou un arbuste
• Statut de conservation : Quasi menacé (NT)
• Évolution démographique : En baisse

The Southern Bristle-Tyrant (*Phylloscartes eximius*) is a small, hyperactive passerine bird found in the subtropical forests of southeastern Brazil, Paraguay, and northeastern Argentina. Its most striking feature is the prominent, stiff "bristles" (modified rictal feathers) at the base of its bill, which help it snatch insects in mid-air. The bird has an olive-green back, a pale yellow belly, and a distinctive white or yellowish eyebrow stripe above a dark eye, giving it a sharp, inquisitive expression. A special trait is its high-pitched, buzzing call and its unique foraging style: it constantly flicks its wings and tail while gleaning prey from the undersides of leaves, often hanging upside down like a tit. Despite its bold behavior, its small size and dense forest habitat make it a challenging but rewarding sight for birdwatchers.

Faits amusants

This tiny, hyperactive bird is a master of the "wing-flick" display, rapidly snapping its wings open and shut while foraging, a behavior thought to startle hidden insects into revealing themselves. Its scientific name *eximius* means "select" or "distinguished," but it's also a relentless counter-singer, able to match and immediately reply to the calls of neighboring bristle-tyrants in rapid-fire vocal duels. Unlike many flycatchers, it often joins mixed-species flocks, acting as a sentinel by giving high-pitched alarm calls that are ignored by larger birds but heeded by smaller ones, a clever survival adaptation. It also possesses unusually long, rigid rictal bristles (the stiff feathers around its beak) that function like a net, helping it snag tiny flying insects mid-air with exceptional precision.

Habitats et répartition

The Southern Bristle-Tyrant is found in the interior Atlantic Forest of southeastern Brazil, eastern Paraguay, and northeastern Argentina (Misiones). It primarily inhabits the mid-story and canopy of humid, mature lowland forests, as well as adjacent tall secondary growth and forest edges. This bird is closely associated with dense vine tangles and epiphyte-laden branches, often occurring below 1,000 meters in elevation but locally up to 1,500 meters. Its distribution is fragmented due to habitat loss, and it is generally rare within its limited range, which extends from southern Bahia and Minas Gerais in Brazil south to northern Rio Grande do Sul.

Comportements & Reproduction

The Southern Bristle-Tyrant is generally observed alone or in pairs, suggesting a monogamous social structure during the breeding season, though detailed studies on long-term pair bonds are scarce. Mating habits are not well documented, but like many tyrant-flycatchers, courtship likely involves vocalizations and simple aerial displays. A unique reproductive strategy is its reliance on constructing a domed nest with a side entrance, often woven from moss and plant fibers and suspended from a branch fork, which provides camouflage and protection from predators and weather. The female typically lays two eggs, and both parents share incubation and feeding duties, a common cooperative strategy among its relatives.

Alimentation

The Southern Bristle-Tyrant is an insectivorous bird, with its diet consisting almost entirely of small arthropods. It primarily forages for a variety of insects and spiders, often picking them from the undersides of leaves and branches in the forest understory. An interesting fact about its feeding behavior is that it frequently employs a technique called "sally-gleaning," where it makes short, swift flights from a perch to snatch prey from foliage before returning to the same or a nearby spot. Additionally, it is known to join mixed-species foraging flocks, allowing it to exploit a wider range of insect prey while benefiting from the group's vigilance against predators.

Couleurs

The Southern Bristle-Tyrant is a small, olive-green bird with a pale yellow belly and throat. Its most distinctive features are a grayish head with a prominent white supercilium (eyebrow stripe) and a white crescent below the eye, giving it a masked appearance. The wings are dark with two pale yellowish wing bars, and the tail is long and often cocked. This subtle, dappled coloration provides excellent camouflage in the dappled light of its forest understory habitat.