Straneck's Tyrannulet

Overview

Straneck's tyrannulet (Serpophaga griseicapilla), also known as the monte or grey-crowned tyrannulet, is a small bird in the family Tyrannidae. It is found in parts of South America, including Argentina, Bolivia, Brazil, Paraguay, and Uruguay, and is currently assessed as Least Concern by the IUCN.

Identification

• Measures 9 to 11 cm in length and weighs between 4.4 and 7.5 g.
• Features a gray crown with a hidden bit of white on some black central crown feathers, a thin white supercilium, and a white crescent under the eye.
• Upperparts are olivaceous brown, with wings that are dusky brownish gray and display two cinnamon to whitish wing bars.
• Possesses a black bill and black legs and feet, with a hazel-brown to dark brown iris.

Habitat

During the breeding season, the species inhabits the Monte Desert in Argentina and potentially the Gran Chaco dry forest in Bolivia. Outside the breeding season, it occupies habitats such as the Chaco, the Argentine Espinal, Pampas grasslands, and lowland moist forests. It occurs at elevations ranging from approximately 30 to 2,280 m.

Diet

The bird feeds on arthropods, moving through vegetation with short jumps and flutters. Its foraging range extends from very near the ground up to at least 6 m above it.

Did you know?

The only known nest of this species was discovered in Argentina 'ready for eggs' in early November, located 1.2 m above the ground within Prosopidastrum angusticarpum shrubs, though nothing else is known about its breeding biology.