In the genus Sicalis, the yellow-finches, this is certainly the most widespread species and the only one that ventures north of the Isthmus of Tehuantepec. Given the huge range, and the fact that the distribution is broken up into various subpopulations, a moderate amount of geographic variation has been described. The southern and often migratory population has at times been separated as a separate species, the Misto Yellow-Finch. It is quite likely that within Grassland Yellow-Finch there are more than one species level taxa, but not enough work has been done either on vocalizations, morphology and DNA to sort this all out. In general the species takes various types of open, grassy habitats, including agricultural areas. The southern cone lowland form (the Misto) is common and widespread, and found almost anywhere an open area with some grass is to be found, including empty lots in towns as well as native habitats like Pampas Grasslands. The Andean populations are more fragmented and found in moister grassy habitats, so absent from dry Puna Grasslands and may even be considered more of a marsh-grass inhabitant. The more tropical lowland populations in Mexico and Central America, as well as Venezuela take various short grass habitats. Unlike most species in the genus, the Grassland Yellow-Finch performs a beautiful song, often while in flight. This flight song is comprised of various trills at different pitches, giving the effect of the song of captive canaries. They give a two note flight call that is quite distinctive once learned. In the non-breeding season Grassland Yellow-Finches form small flocks, although the migratory birds that winter in eastern Bolivia may form large flocks in the thousands there.