The AOS classification treats the Blue-black Grosbeak as Cyanoloxia cyanoides. A report from northwestern Peru documents the subspecies C. c. cyanoides in scrub that differs from its usual humid-forest setting.
Adult males are blue-black, with darker wings, tail, and lores, plus a bright blue forehead. The base of the black bill is silvery.
It is usually found in dense undergrowth in humid forest, at forest edges, or in nearby secondary vegetation. In Piura, repeated records came from dry scrub, which the paper calls atypical for this subspecies.
An extinction-risk assessment has not been added yet.