The Thick-billed Siskin is a large siskin of the Andes from Peru to central Argentina and central Chile. This species resembles other Carduelis siskins, particularly the Hooded Siskin (Carduelis magellanica), but its large bill allows easy recognition. A white vent, present in both sexes, is another useful distinguishing characteristic. The Thick-billed Siskin is uncommon in scrub and Polylepis woodland at high elevations. It subsists almost entirely on the seeds, buds, and shoots of the Polylepis trees. Birds generally occur in pairs or small groups, sometimes with other siskins, that feed actively in vegetation or on the ground. Southern populations move north to winter within the range.