Blue-black grassquits inhabit scrublands, grasslands and cultivated landscapes up to 2,600 meters. Outside of the mating season they live in flocks and forage on the ground for grass seeds, berries and insects. During courtship males lift up into the air several times per minute, beating their wings, singing and displaying the
white underside of their wings. Brooding of the 2–3 eggs is carried out by both sexes for 12 days.
Status according to Red List:Least concern (LC)