The Glossy-black Thrush (*Turdus serranus*) is a striking montane songbird native to the cloud forests of the Andes, from Venezuela to Bolivia. True to its name, the male is cloaked in deep, iridescent black plumage that shimmers with a subtle blue or purple gloss in sunlight, contrasting sharply with its bright orange-yellow bill, eye-ring, and legs. A unique feature of this species is its remarkable vocal ability—it produces a rich, fluted song that often mimics other birds and sounds from its environment, making it a master of avian impersonation. Females are more subdued, with dark brown upperparts and paler, mottled underparts. Specializing in foraging for fruit and insects in the understory, this thrush is also notable for its high-altitude adaptability, thriving in elevations up to 3,500 meters, where its glossy coat helps it stand out against the misty, green backdrop of its cloud forest home.

Faits amusants

The Glossy-black Thrush has a peculiar habit of repeatedly flicking its wings and tail while foraging, a behavior thought to startle insects into movement for easier capture. It is also an adept mimic, known to incorporate the calls of other Andean birds and even mechanical sounds into its own song. Remarkably, this species is one of the few thrushes that will actively follow army ant swarms, snatching up fleeing invertebrates that other birds miss. Its high-altitude habitat forces a unique adaptation: it has a larger heart and more oxygen-rich blood relative to its body size to cope with the thin air of the cloud forest.

Habitats et répartition

The Glossy-black Thrush is found in the Andes mountain range, ranging from western Venezuela through Colombia, Ecuador, and Peru, as well as in the highlands of northwestern Argentina and Bolivia. It inhabits humid montane forests, cloud forests, and elfin woodlands, typically at elevations between 1,800 and 3,600 meters. This species also occurs in adjacent shrubby areas, forest edges, and secondary growth, often favoring dense understory vegetation and mossy environments near streams or in ravines.

Comportements & Reproduction

The Glossy-black Thrush is generally solitary or found in pairs, especially during the breeding season, with no evidence of complex social structures or cooperative breeding. Mating appears monogamous for the season, with the male defending a territory and attracting a female through song from a prominent perch. The nest is a substantial cup of moss, roots, and mud, typically placed in a tree fork or on a bank, where the female lays two to three pale blue eggs with reddish spots. Incubation is carried out solely by the female for about two weeks, while the male assists with feeding the chicks after hatching. A unique reproductive strategy is the use of moss as a primary nest material, which helps maintain humidity and camouflage in the humid montane forests, and the species may raise two broods in a single season if conditions permit.

Alimentation

The Glossy-black Thrush (Turdus serranus) is primarily a frugivore, with its diet heavily dominated by a wide variety of small, wild fruits and berries collected from the understory and forest edges of its Andean cloud forest habitat. It is known to consume fruits from plants in the families Melastomataceae (such as Miconia) and Rubiaceae, often swallowing them whole. However, it is not exclusively a fruit-eater; it also opportunistically supplements its diet with small invertebrates, including beetles, caterpillars, and earthworms, which it forages for by hopping along the forest floor and turning over leaf litter. An interesting dietary adaptation is its role as a key seed disperser for many high-altitude plants, as the thrush’s gut passage can enhance seed germination rates. Additionally, during the breeding season, it noticeably increases its intake of protein-rich insects to feed its chicks, shifting temporarily from its usual fruit-heavy consumption.

Couleurs

The Glossy-black Thrush is entirely deep black with a subtle, iridescent blue-gloss on its upperparts, most visible in good light. Its only contrasting marking is a bright orange-red bill and eye-ring, with matching orange legs. It has no camouflage markings; its solid dark coloration likely aids in blending into shadowy, dense Andean cloud forests.