Justification of Red List Category
Trapping pressure and habitat loss are rapidly reducing the very small population of this species, and breeding habitat (and therefore the population) is fragmented. It consequently qualifies as Endangered.
The population size is preliminarily estimated to fall into the band 1,000-2,499 individuals. This equates to 667-1,666 mature individuals, rounded here to 600-1,700 mature individuals.
A rapid and on-going population decline is suspected owing to trapping for the bird trade together with widespread habitat loss and degradation.
Sporophila palustris breeds in Argentina (Corrientes, Entre Ríos and possibly Buenos Aires), Brazil (Rio Grande do Sul), Uruguay (50-100 birds in the río Uruguay basin and 400-600 in the south-east wetlands [A. B. Azpiroz in litt. 1999, 2007]) and possibly south-east Paraguay. It winters in Brazil (Bahia [Souza 1999], Minas Gerais, Goiás, Mato Grosso, Mato Grosso do Sul, São Paulo, Paraná and probably in Tocantins and Santa Catarina) and perhaps north-east Paraguay, but there are very few records. Migrants are regularly recorded in east Paraguay (Lowen et al. 1996, Clay et al. 1998), and north Argentina. It can occur at high densities, but is extremely local and has declined substantially (at least) in Argentina and (to a lesser extent) Uruguay (Pearman and Abadie 1995, A. B. Azpiroz in litt. 1999, 2007). Recent records in Paraguay all refer to single birds, although a record from southern Paraguay in 2005 indicated possible breeding and the species was present in San Rafael National Park through most of 2006 (A. J. Lesterhuis in litt. 2007).
It breeds during the austral summer, in November–February, in inundated grasslands and marshes, showing a strong preference for the latter (Di Giacomo et al. 2010, Vizentin-Bugoni et al. 2013), where patches of Paspalum spp. and areas of Andropogon lateralis containing ripe seeds are favoured (Di Giacomo et al. 2010). Nesting occurs in transition zones between terrestrial and aquatic habitats (Vizentin-Bugoni et al. 2013). At other times, it inhabits various dry and wet grasslands.
Heavy trapping pressure has extirpated the species from parts of Argentina and threatens populations in the río Uruguay basin (A. B. Azpiroz in litt. 1999, 2007). Potential breeding sites are intensively grazed, and some have been completely trampled by cattle (Vizentin-Bugoni et al. 2013). Rapid afforestation with Eucalyptus and Pinus spp. (Pearman and Abadie 1995, World Bank 1995, Di Giacomo et al. 2010, Clay et al. in prep.) is even affecting wet valley bottoms, regardless of poor tree growth (R. Davies verbally 1998). Pesticides and other chemicals are carried by drainage and run-off into marshes (Clay et al. in prep.). In south-east Uruguay, there has been extensive drainage for agriculture and this is continuing at a local scale (A. B. Azpiroz in litt. 1999, 2007). Mechanised agriculture, invasive grasses and annual burning additionally threaten winter and migration habitats (Stotz et al. 1996, Parker and Willis 1997). In southern Paraguay, and perhaps parts of Uruguay and Argentina seasonally inundated grasslands and marshes where the species might have breeding populations are being converted to rice fields (A. J. Lesterhuis in litt. 2007).Unfavourable artificial burning regimes degrade grassland habitat (Vizentin-Bugoni et al. 2013).
Conservation Actions Underway
A CMS Memorandum of Understanding targeting this and other southern South American grassland species has recently been approved by Argentina, Brazil, Paraguay and Uruguay (A. B. Azpiroz in litt. 1999, 2007). It is legally protected in Brazil, Paraguay and Uruguay, and trapping is prohibited in Argentina and Uruguay, although this is not effectively enforced (A. B. Azpiroz in litt. 1999, 2007). It breeds at Mata Grande Biological Reserve, Rio Grande do Sul, Brazil (Vizentin-Bugoni in litt. 2011), Potrerillo de Santa Teresa Reserve, Uruguay (A. B. Azpiroz in litt. 1999, 2007), and Iberá Provincial Reserve, Argentina (Chebez et al. 1998). Emas National Park, Brazil, is possibly an important wintering site, and it has also been recorded in Espinilho Ecological Park, Ibirapuitã and São Donato Biological Reserves and Itirapina Ecological Station (E. Machado in litt. 2007). In Paraguay, it occurs in San Rafael National Park (within which two areas are protected by Guyra Paraguay) and Reserva Isla Yacyreta, where an ongoing monitoring scheme is studying threatened grassland birds (A. J. Lesterhuis in litt. 2007). Migrating birds occur in several Paraguayan and Argentine reserves. The species has been heavily exploited, but it is unclear if it has been bred in any volume.
10 cm. Small, distinctive seedeater. Male has white throat, cheeks and upper breast contrasting strongly with rufous-chestnut lower underparts and rump. Grey crown and mantle. Slightly darker wings and tail, fringed paler. White patch at base of primaries. Female inseparable from females of other Sporophila spp. Similar spp. Voice Spirited series of high-pitched whistles and melancholic chíuu calls. Hints Often associates with other grassland Sporophila spp.
Text account compilers
Pople, R., Mazar Barnett, J., Sharpe, C.J., Capper, D., Symes, A.
Azpiroz, A., Davies, R., Lesterhuis, A., Machado, É., del Castillo, H. & Vizentin-Bugoni, J
BirdLife International (2021) Species factsheet: Sporophila palustris. Downloaded from http://www.birdlife.org on 06/03/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/03/2021.