Dubois´s Seedeater

Belongs to the family Thraupidae and is a diminutive passerine bird measuring roughly 10 to 11 centimeters in total length, with an overall body mass ranging between 8.5 and 11 grams. It displays pronounced sexual dimorphism in both plumage pattern and coloration. Adult males in breeding condition exhibit an unmistakable appearance characterized by deep slate-gray dorsal plumage across the mantle and scapulars. The head is adorned with a prominent jet-black hood covering the crown, forehead, lores, and cheeks, extending downwards into a solid black bib over the throat and uppermost breast. This dark bib contrasts sharply with the rest of the underparts, as the lower breast, belly, and undertail coverts are clean white, occasionally showing faint grayish mottling along the flanks. Its bill is stout, distinctly conical, and colored in a pale creamy ivory or soft yellow, occasionally displaying a darker culmen. In contrast, females lack any strong black-and-white contrasts, showing an unassuming olive-brown dorsal coloration that shades into a pale buffy yellowish on the breast and abdomen, paired with an entirely dusky or blackish bill. Immature birds of both sexes mirror the subdued plumage of adult females until young males acquire their definitive adult feathering through gradual post-juvenile molts.

Geographical distribution: Is an endemic taxon of eastern and southeastern South America, restricted entirely to the biome corridors of Brazil. Its established distribution spans fragmented populations across the states of Minas Gerais, Espírito Santo, Rio de Janeiro, southern Bahia, and localized sectors of eastern and northern São Paulo. While geographically bounded to this regional belt, the species is known to make non-migratory seasonal movements tracking the local phenology and seeding cycles of native grasses.

Habitat: Inhabits open and semi-open grassy landscapes primarily associated with the Atlantic Forest domain and its transition ecotones into the Cerrado. It commonly frequents tall undisturbed grasslands, damp pastures, shrubby savannas, weedy fallow fields, regenerating secondary scrub, and riparian vegetation borders. Its altitudinal range extends from near sea level along the coastal plains up to approximately 1,200 meters above sea level, successfully occupying agricultural edges and rural outskirts provided that dense, tall standing grasses remain available.

Feeding: Is predominantly granivorous, exhibiting morphological and behavioral adaptations optimized for foraging on seeds of various grasses belonging to the family Poaceae. The bird feeds actively by clinging to grass stems in acrobatic postures, using its robust conical bill to husk and extract ripening seeds directly from the inflorescences. During the reproductive phase and the annual feather molt, this granivorous baseline is supplemented with animal protein obtained from small invertebrates, such as minute beetles, caterpillars, and aphids, which are essential for fulfilling heightened nutritional and metabolic demands.

Behavior: Displays diurnal activity and exhibits strong social tendencies during the non-breeding period, often gathering in mixed-species aggregations alongside other seedeater species within the genus Sporophila. These flocks roam open fields cooperatively in search of food patches. However, with the onset of the austral spring, males shift toward intense territoriality. Individual males stake out breeding territories by perching prominently atop tall bushes, fence lines, or emergent grass stalks, delivering rapid, high-pitched, musical vocalizations characterized by a series of thin whistles and accelerated metallic trills designed to deter rivals and court females.

Nesting: Occurs primarily throughout the austral spring and summer rainy season, syncing with optimal seed abundance. The female undertakes the construction of a delicate, open cup-shaped nest, using thin stems of dried grass, fine plant rootlets, and fibers securely bound together with spider cobwebs to create a lightweight, somewhat translucent basket. The nest is typically anchored low down, between 0.5 and 2 meters above the ground, hidden within dense clumps of grass or inside a leafy shrub. The clutch typically consists of 2 to 3 eggs, which are pale creamy white patterned with distinct brown and purplish speckles concentrated around the broader end. Incubation is conducted exclusively by the female for 12 to 13 days. Both parents participate in feeding the altricial nestlings through regurgitation, and the young fledge successfully after a nestling period of 10 to 14 days.

Conservation status: Is currently evaluated as Least Concern (LC) on the global Red List maintained by the International Union for Conservation of Nature (IUCN). Nevertheless, regional populations face notable anthropogenic pressures, foremost among which is intense illegal trapping driven by the cagebird trade, which targets singing males. Additionally, extensive habitat alteration resulting from urban sprawl, regular pasture burning, and the widespread application of chemical herbicides in agricultural landscapes systematically reduces the availability of essential wild grass species.