Mouse-colored Antshrike
Thamnophilus murinus
The mouse-colored antshrike is 13 to 14 cm (5.1 to 5.5 in) long and weighs 17 to 20 g (0.60 to 0.71 oz). Members of genus Thamnophilus are largish members of the antbird family; all have stout bills with a hook like those of true shrikes. This species exhibits significant sexual dimorphism. Adult males of the nominate subspecies have gray upperparts with a hidden white patch between their scapulars. Their wings are dark yellowish brown that is somewhat rufous in the eastern part of its range; their wing coverts are grayer with buffy white tips. Voice: The mouse-colored antshrike's song is "slightly accelerating series of up to c. 15 similar notes". It has been written as "arr arr arr-arr wee'AWR". Its main call is "nasal and abrupt"; others are "a flat, raspy whine", "a clear note that becomes a raspy growl", "variable whines", and "abrupt notes".
ID text from Wikipedia, CC BY-SA 4.0

Uniform Antshrike
Thamnophilus unicolor
The uniform antshrike is 14.5 to 17 cm (5.7 to 6.7 in) long and weighs about 24 g (0.85 oz). Members of genus Thamnophilus are largish members of the antbird family; all have stout bills with a hook like those of true shrikes. This species exhibits significant sexual dimorphism. Adult males of the nominate subspecies are mostly deep gray or blackish gray. They sometimes have white tips on their outer tail feathers. Adult females have a rufous crown and a gray face. Their upperparts are rufous brown and their underparts pale rufous brown. Immatures of both sexes are similar to adult females. Voice: The uniform antshrike's song has been described as "a simple short series of nasal notes, each note sometimes with rising inflection, 'anh, anh, anh, anh' (sometimes 3 or 5 notes)" and as "a slightly accelerating and rising, slow series of 4–8 high, descending notes NYAH NYAH-nyah-nyah". The song of subspecies T. u. caudatus is similar to that of the other two but higher pitched.
ID text from Wikipedia, CC BY-SA 4.0

Where you might meet both
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Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: Mouse-colored Antshrike and Uniform Antshrike.