The Blue-black Grassquit is a small bird found widely in grasslands and farmland from Mexico to South America. During courtship, the male jumps upward and reveals white shoulder patches.
The male is glossy blue-black with white underwings. Females and juveniles are brownish.
It mainly eats small seeds but also takes insects. Males perform an upward jumping display during courtship.
An extinction-risk assessment has not been added yet.