Lesser Grass-Finch Emberizoides ypiranganus Scientific name definitions

The Lesser Grass-Finch is very similar to and broadly sympatric with the Wedge-tailed Grass-Finch (Emberizoides herbicola). The two are so similar in appearance that the status of the Lesser Grass-Finch is probably underestimated due to misidentification. In terms of plumage the Lesser Grass-Finch has a grayish face, and streaked flanks but most obvious is its rasping and chattering song that is quite different from the sweet whistles of the Wedge-tailed Grass-Finch. The Lesser Grass-Finch is found in dense and complex grasslands, often at the edge of wetlands or shrub patches. Little is known about its nesting and other behaviors. It is restricted to the area of NE Argentina, E Paraguay, N Uruguay and SE Brazil.

Paraguay (largely E of R Paraguay), NE Argentina (E Formosa, E Chaco, NE Santa Fe, Corrientes and E Entre Ríos), SE Brazil (S Minas Gerais, S São Paulo, SW Rio de Janeiro and S Paraná S to Rio Grande do Sul) and N & C Uruguay.

Season Nov–Jan. Little known. Rarely performs aerial song display. Two nests described from Brazil (Serra do Cipó National Park, in Minas Gerais), each a relatively deep cup, some dried leaves of Panicum loreum at base, lined with floral peduncles of Leiothrix cf. spiralis, placed 12–14 cm above ground at base of Lagenocarpus tenuifolius (2 Rodrigues, M., Costa, L.M., Freitas, G.H.S., Cavalcanti, M. and Dias, D.F. (2009). Ninhos e ovos de Emberizoides herbicola, Emberizoides ypiranganus e Embernagra longicauda (Passeriformes: Emberizidae) no Parque Nacional da Serra do Cipó, Minas Gerais, Brasil. Revista Brasileira de Ornitologia. 17(2): 155–160. In Portuguese with English summary. Close ); in Argentina nests 7–70 cm above ground, e.g. in midst of clump of Paspalum intermedium grass, one nest had external diameter 6·5–7 cm, internal diameter 4–4·5 cm, external height 6 cm and internal depth 5 cm (3 Di Giacomo, A.G. (1998). Descripción del nido y huevos de Emberizoides ypiranganus, y presencia de la especie en Formosa, Argentina. Hornero 15(1): 51-52. In Spanish with English summary. Close ). Clutch 2–3 eggs, white with few reddish, brown or black spots at broad end. In a study in upland grasslands of S Brazil (93 nests, 2012–2014) season early Oct–early Mar; mean clutch size 2·7 ± 0·5 eggs (n = 52); eggs, 21·9 mm × 15·9 mm on average (n = 17); incubation exclusively by the female, during 13–14 days; hatching rate 94% (n = 154 eggs); nestling period 10·6 ± 0·7 days (range 9–12, n = 27 nests); nestlings opened their eyes on the fifth day of life, and their weight when leaving the nest was c. 17 g ;  in most nests, both parents fed the nestlings; breeding success was c. 40%; predation was the main cause of failure, affecting 76% of the unsuccessful nests; re-nesting interval after nest failure, 2·7 days, and up to four attempts by the same female observed in the same breeding season (4 Chiarani, E. and Fontana, C.S. (2015). Breeding biology of the Lesser Grass-Finch (Emberizoides ypiranganus) in southern Brazilian upland grasslands. Wilson J. Orn.. 127(3):441–456. Close ).

Not globally threatened (Least Concern). Uncommon to fairly common throughout range.

Alvaro began birding as an 11 year old in Canada, and eventually trained in Evolutionary Ecology studying, creatures as varied as leaf-cutter ants and Argentine cowbirds. But his career has been focused on birding tourism, both as a guide and owner of his tour company, as well as a avitourism consultant to various organizations. He is the author of Birds of Chile, New World Blackbirds: The Icterids, as well as the ABA Field Guide to the birds of California. He lives in Half Moon Bay, California where he is known for his pelagic birding trips. Email: alvaro@alvarosadventures.com.