Highly distinctive and unusual species that is more reminiscent of a large seedeater. It has a unique migration pattern, breeding during the rainy season in the Tumbes eco-region in northwestern Peru and southwestern Ecuador and wintering in the western Amazon. The male is hard to mistake for any other species; notably larger than any similarly-patterned seedeater in range, with a longer, thinner bill. Females are dingy greenish overall, with a pale yellow belly faintly streaked with olive. Combination of size and shape, and association with males of this species should clinch the ID.