Large-billed Seed-Finch

The large-billed seed finch is 13.5 to 14.5 cm (5.3 to 5.7 in) long and weighs about 20 to 28 g (0.71 to 0.99 oz). It has a short bill with a very deep base and a rounded culmen. The species is sexually dimorphic. Adult males of the nominate subspecies S. c. crassirostris are almost entirely black with white underwing coverts and white bases on the primaries that show as a small patch on the closed wing. Adult females have a warm brown head and upperparts. Their tail and wings are a slightly darker brown with white underwing coverts; they lack the male's white primary patch. Their throat and underparts are pale buff-brown. Males of subspecies S. c. occidentalis have a smaller white wing patch and darker underwing coverts but are otherwise like the nominate. Females are like the nominate. Both sexes of both subspecies have a very dark iris. Males have an ivory-white bill and black legs; females have a blackish bill and dark legs. Juveniles resemble adult females.

The nominate subspecies of the large-billed seed finch is the more northerly of the two and has the much larger range. It is found from Santander Department in north-central Colombia south intermittently through eastern Ecuador into northeastern Peru. It also found at sites across northern Colombia. From Colombia and Peru its range continues east very slightly into western Brazil's Amazonas state and into Venezuela. In Venezuela it is found on both sides of the Andes, along the Coastal Range, and inland from the coast across the northern third of the country including far northern Bolívar state. It also is found in far southeastern Bolívar and possibly across the rest of the state and into eastern Amazonas state. From Venezuela its range continues across the Guianas and Brazil's Amapá and far northern Pará states. Several taxonomic lists do not include Panama in the species' range. However, it was documented in the country in 2011 and there are many eBird records since then. Subspecies S. c. occidentalis is found along Colombia's Western Andes and intermittently through western Ecuador. The status of the nominate subspecies in Trinidad is uncertain. The Trinidad & Tobago Bird Status & Distribution Committee does not include it in its checklist. The South American Classification Committee includes it as an extirpated species. …

The large-billed seed finch feeds primarily on seeds and is thought to also include small numbers of insects in its diet. It appears to favor seeds of Cyperaceae sedges, perhaps due to its large bill. It plucks seeds while clinging to the plant stalk or an adjacent one and also takes them on the ground. It usually forages singly or in pairs though sometimes in small flocks that can include other seed-eating species.