Masked Water-Tyrant

The masked water tyrant is 14.5 to 15 cm (5.7 to 5.9 in) long. The sexes have the same plumage. Adults are mostly white. They have a black stripe through the eye (the eponymous mask), a brownish gray tinge to the back, black wings, and a black tail with white feather tips. They have entirely white underparts. Subspecies F. n. atripennis has blacker wings than the nominate with white fringes on the tertials; the amount of white is variable. Both subspecies have a dark iris, a black bill, and black legs and feet.

The masked water tyrant has a highly disjunct distribution. The nominate subspecies has by far the larger range of the two. It is found mostly in eastern and southern Brazil, from eastern Pará and Tocantins east to Rio Grande do Norte and from there south to Mato Grosso do Sul and Santa Catarina. Its range extends into far northeastern Argentina's Misiones Province and it has been recorded as a vagrant in Paraguay and Uruguay. Subspecies F. n. atripennis is found from extreme southwestern Colombia's Nariño Department south through western Ecuador slightly into far northwestern Peru's Tumbes Department. The masked water tyrant inhabits somewhat open shrublands near freshwater bodies, and especially favors marshy areas and rice fields. It also occurs on the banks of ponds, lakes, streams, and rivers and occasionally is found in nearby open grasslands. It has increasingly been found in urban and suburban parks in Brazil. The nominate subspecies occurs mostly at elevations from sea level to about 300 m (1,000 ft) but occasionally much higher. Subspecies F. n. atripennis mostly occurs below 800 m (2,600 ft) in Ecuador.

The masked water tyrant feeds on insects. It usually forages singly or in pairs and tends to be tame and conspicuous. It usually forages near or on the ground and on floating and emergent vegetation. It captures prey with short sallies, quick runs, and upward leaps.