[[File:Swallow_Tanager_male.jpg|thumb|A male Swallow Tanager]]
The Swallow Tanager (Tersina viridis) is a species of bird in the family Thraupidae. It is the only member of the genus Tersina. Its unique morphology and behavior, particularly its aerial foraging style, distinguish it from other tanagers and give it its common name.
Description
The Swallow Tanager is a medium-sized passerine, typically measuring around 14.5–15 cm (5.7–5.9 in) in length. It exhibits marked sexual dimorphism:- Males: Are strikingly colored with iridescent blue-green plumage on their upperparts and a distinct black mask extending from the lore through the eye and down to the throat. Their underparts are pure white. They possess a short, broad, and somewhat flattened bill that is slightly hooked at the tip, well-adapted for catching insects in flight.
- Females: Are generally duller, with less iridescent green-blue upperparts and lacking the black mask and throat. Their underparts are yellowish-green, heavily barred or scaled with dark markings, particularly on the breast and flanks.
- Juveniles: Resemble females but are typically duller in coloration.
Taxonomy and Systematics
The Swallow Tanager belongs to the order Passeriformes and the family Thraupidae, which encompasses a wide variety of tanagers. It is the sole species within the monotypic genus Tersina, highlighting its evolutionary distinctiveness within the family. Genetic studies have placed it within the core tanager group, despite its unusual appearance and behavior.Distribution and Habitat
The Swallow Tanager is widely distributed across South America, with its range extending from eastern Panama and Colombia, south through the Andes to Bolivia, and across much of Brazil, Paraguay, and northern Argentina.It inhabits a variety of humid tropical and subtropical environments, including:
- Forest edges
- Clearings
- Secondary growth
- Plantations
- Gallery forests
- Areas near streams and rivers
They are typically found at elevations ranging from sea level up to approximately 1,700 meters (5,600 ft), though they can occasionally be observed higher in some parts of their Andean range.
Behavior and Ecology
Diet
The Swallow Tanager is primarily frugivorous, feeding on a wide array of fruits and berries. However, a significant portion of its diet also consists of insects, which it often catches in agile aerial pursuits, reminiscent of true swallows, by sallying out from an exposed perch.Breeding
Uniquely among tanagers, the Swallow Tanager is a cavity nester. It typically utilizes:- Earthen banks, where it digs its own burrow or uses abandoned burrows of other species (e.g., kingfishers).
- Holes in trees.
- Crevices in rock faces.
Females lay a clutch of 2-3 white eggs. Both parents are thought to participate in the care and feeding of the young.