Unicolored Antwren

Myrmotherula unicolor

Uncommon small, short-tailed antwren of the lower and middle levels of humid forests. Very active and often follows mixed-species flocks. Males are uniform gray with a small dark throat patch, while females are uniformly brown-gray, with less gray in the head than female Salvadori’s Antwrens.

Identification

The unicolored antwren is 9 to 10 cm (3.5 to 3.9 in) long and weighs 6.5 to 8 g (0.23 to 0.28 oz). It is a smallish bird with a short tail. Adult males are almost entirely gray, with lighter underparts than upperparts. Their throat feathers have black bases and gray tips. Adult females have olive-brown upperparts with a grayish tinge on the crown and nape and yellowish brown uppertail coverts. Their wings are dark grayish brown with reddish yellow-brown edges on the flight feathers. Their tail is reddish yellow-brown. Their throat is whitish and their underparts mostly olive-buff that is grayer on their sides and flanks. Their crissum is brownish yellow.

Taxonomy

The unicolored antwren and the Alagoas antwren (M. snowi) were previously considered conspecific and now form a superspecies. The unicolored antwren is monotypic. The unicolored antwren, the Yungas antwren (M. grisea), the Alagoas antwren (M. snowi), and the plain-winged antwren (M. behni) appear to form a monophyletic group with similar vocalizations and habitat requirements.

Scientific name
Myrmotherula unicolor
Authority
(Ménétriés, 1835)
Order
Passeriformes
Family
Thamnophilidae
Genus
Myrmotherula

Range and habitat

The unicolored antwren is a bird of the Atlantic Forest. It is found along coastal southeastern Brazil from northern Rio de Janeiro state south into northern Rio Grande do Sul. It inhabits the understorey to mid-storey of evergreen forest and mature secondary forest. In a few areas it also occurs in restinga woodlands that grow on white-sand soils. It favors dense viny understory in somewhat stunted forest with a canopy up to about 20 m (70 ft) high. In elevation it ranges from sea level to about 500 m (1,600 ft).

Migration
Resident species

Behavior

Migration pattern: Resident species.

Conservation

Population trend: declining.

Population trend
declining

Photos

Distribution

Bird Calls

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