Marsh Antwren

The marsh antwren is 13 to 15 cm (5.1 to 5.9 in) long and weighs 8 to 12 g (0.28 to 0.42 oz). Adult males of the nominate subspecies have an ill-defined pale supercilium and a whitish crescent below the eye on an otherwise lead gray face. Their forehead is grayish white and their crown and upperparts dark chestnut-olive. Their wings are blackish with chestnut-olive edges on the flight feathers. The wing coverts are darker than the flight feathers and have bright white tips. Their tail is black, sometimes with white or cream tips on the outer feathers. Voice: The song of the marsh antwren's nominate subspecies is "doublets of abrupt notes, the first note typically more intense and lower-pitched...repeated in slightly unevenly and variably paced series". That of F. a. paludicola is "a sequence of rapidly but evenly repeated double-note phrases (the first note slightly descending, the second ending in a small upward and downward modulation)".