Chestnut-backed Antshrike

The Chestnut-backed Antshrike, a member of the Thamnophilidae family, is a bird of notable stature within the antbird community, boasting a robust bill with a shrike-like hook. This species, with a length of 16 to 17 cm and a weight of 26 to 28 g, is adorned with a distinctive crest and exhibits sexual dimorphism.

Identification Tips

Adult males of the nominate subspecies, Thamnophilus palliatus, are characterized by a black crown with white spots on the forehead, a face and nape speckled with white, and rufous-brown upperparts, wings, and tail. Their throat is striped black and white, while the rest of the underparts feature black and white bars with a rufous hue on the flanks. Females mirror the males but with a deep rufous-brown crown and broader white bars on the underparts. Both sexes possess a pale iris, the color of which may vary. Subadults share similarities with adults but have their own distinct markings.

Habitat

The Chestnut-backed Antshrike thrives in a variety of somewhat open landscapes, including forest edges, mature secondary forests, regrowing clearings, and abandoned plantations rich in bamboo. It also inhabits várzea and Guadua bamboo stands in the Amazonian lowlands, as well as shrubby parks and gardens in southeastern Brazil.

Distribution

This species has a disjunct distribution across Bolivia, Brazil, and Peru. It is found in coastal eastern Brazil, southeastern Peru, northern Bolivia, and Brazil south of the Amazon, with each subspecies occupying a specific region.

Behaviour

Presumed to be a year-round resident, the Chestnut-backed Antshrike forages alone or in pairs, often joining mixed-species feeding flocks. It is adept at navigating dense vegetation, from ground level to 15 meters high, in search of prey.

Song & calls

The song of the Chestnut-backed Antshrike is a captivating series of accelerating, somewhat nasal notes that rise slightly at the beginning and fall more distinctly towards the end, culminating in a longer, downslurred note. Its calls include a short nasal note and an upward-inflected squeal.

Breeding

The breeding season is not fully defined but is observed from October to January in southeastern Brazil and possibly from November to June in Amazonian Brazil. The nest is a small, deep cup suspended in a branch fork, typically within a dense thicket.

Similar Species

The Chestnut-backed Antshrike can be distinguished from similar species by its unique coloration and vocalizations.

Diet and Feeding

While the full details of its diet are unknown, it includes insects and arthropods such as spiders. The bird is known to follow army ant swarms in eastern Brazil, capitalizing on the disturbances caused by the ants to catch prey.

Conservation status

The IUCN has classified the Chestnut-backed Antshrike as Least Concern. It is fairly common within its large range and is found in several protected areas. Adapted to various habitats, including disturbed woodlands and second growth, the species is considered to have low vulnerability.