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

Plain-winged Antshrike
Thamnophilus schistaceus
The plain-winged antshrike is 13 to 14 cm (5.1 to 5.5 in) long and weighs 19 to 21 g (0.67 to 0.74 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 almost entirely gray, with slightly darker upperparts than underparts. Their wings and wing coverts have a slight brownish tinge. Adult females have a rufous crown and a grayish face. Their upperparts are yellowish olive-brown and their underparts pale olive-brown. Voice: The plain-winged antshrikes's song differs somewhat among the subspecies. In general it is "a slightly accelerating series of similar notes at same pitch, ending in sharply downslurred note that 'falls off' to a lower pitch". Both the number of notes and pace vary; the song of subspecies T. s.
ID text from Wikipedia, CC BY-SA 4.0

Where you might meet both
Learn this pair in the BeakBrain App
Photo and call practice. Coming soon to iPhone and Android.
Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: Mouse-colored Antshrike and Plain-winged Antshrike.