The sooty tyrannulet (Serpophaga nigricans ) is a species of bird in the family Tyrannidae, the tyrant flycatchers. It is small, usually weighing 9 grams with a length of 12 centimeters, and has gray or brownish-grey feathers with black tail feathers.It is found in Argentina, Brazil, and Uruguay; also southern Paraguay. A small extension of its range is in southeastern Bolivia.
Its natural habitats are subtropical or tropical moist shrubland, rivers, and swamps.
