Leaden Antwren

Overview

The leaden antwren (Myrmotherula assimilis) is a small passerine bird belonging to the family Thamnophilidae. It is classified as a species of Least Concern by the IUCN, with a population that is believed to be decreasing despite no immediate threats being identified.

Identification

• Length of 9 to 10.5 cm with a short tail.
• Adult males have medium gray upperparts with a hidden white patch between the shoulders, while females are brownish gray to olive gray.
• Males possess an all-black bill, whereas females have a black maxilla and a gray mandible.
• Both sexes have brown irises and blue-gray legs and feet.
• The song is an accelerating, descending trill transcribed as "tew tew-tew-tew'tew'tew'tew'tu'tu'teerrrrrrru", and the call is a short, downslurred snew.

Habitat

Found in Bolivia, Brazil, Colombia, and Peru, this species inhabits the understory of tall Cecropia forest on islands in the Amazon River and its major tributaries. It locally occurs along river banks and the shores of oxbow lakes, requiring an understory composed of multiple species in addition to Cecropia.

Diet

The diet consists mostly of insects and probably spiders. The bird forages singly, in pairs, or in family groups, actively gleaning prey from live and dead leaves and bark mostly between 1.5 and 7 m above the ground, though occasionally as high as 15 m.

Did you know?

Although its breeding season includes October, almost nothing else is known about the species' breeding biology.