This discussion was first published as part of the 2016 Red List update. At the time a decision regarding its status was pended, but to enable potential reassessment of this species as part of the 2017 Red List update this post remained open and the date of posting was updated.
Chestnut Seedeater breeds in north-eastern Argentina, southern Paraguay, western and south-eastern Uruguay and extreme southern Brazil. It winters largely in central Brazil and eastern Paraguay. The species is currently listed as Vulnerable under A2cde+3cde+4cde; C2a(i). A rapid and on-going decline is suspected, owing to trapping for the bird trade, compounded by habitat loss and degradation. The population is estimated to number 2,500-9,999 mature individuals with <1,000 mature individuals in each subpopulation.
In 1969, there were c.100 males at Arroyo Barú and Arroyo Perucho Verna, Argentina, but only one singing male at Arroyo Barú in 1992 (Pearman and Abadie 1995). Surveys in 1991-1993 found no more than eight males at any site in Argentina (Pearman and Abadie 1995). In 1998, there were 23 males at Ñu Guazu, Paraguay (R. P. Clay in litt. 1999) but only two were found here in November 2006 and the majority of records since 2004 relate to single birds (A. B. Lesterhuis in litt. 2007). Heavy trapping pressure is compounded by extensive conversion within the species’s grassland habitat. Rapid afforestation with Eucalyptus and Pinus spp. (Pearman and Abadie 1995, World Bank 1995, Clay et al. in prep.) is even affecting wet valley bottoms, regardless of subsequent poor tree growth (R. Davies verbally 1998). Pesticides and other chemicals are carried by drainage and run-off directly into marshes (Clay et al. in prep.). Mechanised agriculture, invasive grasses and annual burning additionally threaten winter and migration habitats (Stotz et al. 1996, Parker and Willis 1997). In southern Paraguay seasonally inundated grasslands and marshes are being converted to rice fields and this has already taken place in much of the Ñu Guazu area since the species was recorded there in 1998 (A. B. Lesterhuis in litt. 2007).
In the Brazilian Red List assessment for birds (MMA 2014) this species is listed as Near Threatened. Given that Brazil represents a large proportion of the global wintering range, should the species be downlisted to Near Threatened globally?
Up-to-date information is requested on the species’s population size, structure and population size reduction. Is the global population likely to be >10,000 mature individuals or is the number of mature individuals in each subpopulation >1,000? In which case the species would no longer meet the thresholds for Vulnerable under C2a(i). Is the population size reduction likely to be <30% over 10 years or three generations? And is the population in continuing decline? A population size reduction approaching but not exceeding 30% in 10 years or three generations owing to a decline in habitat quality /Area of Occupancy/Extent of Occurrence, exploitation or the effects of introduced taxa or pollutants would likely qualify the species for downlisting to Near Threatened under A2cde+3cde+4cde.
Comments on the proposed changes and any new information are welcome.
Clay, R. P.; Lowen, J.C.; Capper, D. R. in prep. A Paraguayan perspective on grassland conservation in central South America.
MMA (2014) Lista Nacional Oficial de Espécies da Fauna Ameaçadas de Extinção. Portaria No 444, de 17 de dezembro de 2014. Diário Oficial da União – Seção 1. Nº 245, quinta-feira, 18 de dezembro de 2014.
Parker, T. A.; Willis, E. O. 1997. Notes on three tiny grassland flycatchers, with comments on the disappearance of South American fire-diversified savannas. Ornithological Monographs 48: 549-555.
Pearman, M.; Abadie, E. I. Undated. Mesopotamia grasslands and wetlands survey, 1991–1993: conservation of threatened birds and habitat in north-east Argentina.
Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago.
World Bank. 1995. Paraguay: agricultural sector review.