The black-billed scythebill (Campylorhamphus falcularius) is a species of bird in the subfamily Dendrocolaptinae of the ovenbird family Furnariidae.

Their crown and nape are blackish, with thin whitish to ochre streaks that extend onto the upper back.

Their breast has indistinct thin whitish to creamy buff streaks that disappear on the belly and reappear faintly on the undertail coverts.

[4] The black-billed scythebill is found from the Chapada Diamantina in southeastern Brazil's Bahia state south into northern Rio Grande do Sul, in eastern Paraguay's Alto Paraná and Itapúa departments, and in northeastern Argentina's Misiones and Corrientes provinces.

[4] The black-billed scythebill's diet is virtually unknown; the one stomach examined contained only arthropods.

It typically takes its prey by probing crevices and holes in bark, bamboo, bromeliads, and epiphytes.

[1] It is considered rare to locally uncommon in most of its range, though it appears to be fairly common at some southeastern Brazilian sites.