Lesson's Seedeater is a seasonal visitor to the northern lowlands of Bolivia. The Birds of Bolivia account describes it there as a rare, local nonbreeding visitor.
The male has a white cheek patch and a smudgily marked breast. Females can be indistinguishable from female Lined Seedeaters, according to the account.
In northern Bolivia it occurs from about November to May in seasonally flooded savanna, cerrado, grassy or shrubby clearings, forest borders, and riverbanks. It forages low in grass, in pairs or flocks.
An extinction-risk assessment has not been added yet.