[5][6] The slender antbird is found discontinuously in southeastern Bahia and northeastern Minas Gerais states of eastern Brazil.

It captures prey by gleaning, reaching, jumping (upward and to the ground), lunging from a perch, and by searching leaf litter in bromeliads.

[5] Its one known nest was a low cup made of dry leaves and vines resting on a leaf that drooped to the ground.

The time to fledging was not determined because the nest was empty, apparently predated, six days after the young hatched.

The slender antbird's song is a "very high, loud, increasing series of 7-9 rather sharp 'peer' notes without intervals".

"Dry forest in east Bahia has been reduced to scattered fragments by rapid and continuing clearance for cattle pasture as well as clearance for firewood by local communities [and] much of what remains is apparently unsuitable for the species since many woodlots are highly disturbed by livestock.

[9] It does occur in Boa Nova National Park but "[f]urther protected areas are needed, particularly in remnant forests of Minas Gerais".