A small flock of these birds exhibited a bewildering array of plumage variation. Most were streaked on the chest indicating they were immature. Some had strong lateral throat stripes, but others, did not. They spent most of their time foraging on the ground in a wet area. Despite its name, this species is not a finch, but classified with the seedeaters which are now usually included in the tanagers (Thraupidae). This species has a patchy distribution in South and Middle America, with the race S. l. luteiventris ranging in the lowlands of Southern South America and sometimes (e.g. Sibley & Monroe) split as a separate species, the Misto Yellow-Finch. It is characterized by a duller coloration overall but with much individual variation. Grassland Yellow-Finch was formerly considered conspecific with Raimondi's Yellow-finch (Sicalis raimondii) of Peru. Both IOC and H&M remove the hyphen from Yellow-Finch. HBW retains the hyphen but keeps "finch" in lower case.
Digiscoped with Panasonic DMC-LX5 | Nikon FieldScope 3 | 30X WA | hand-held (no adapter)