Leistes defilippii (del Hoyo and Collar 2016) was previously placed in the genus Sturnella following SACC (2005 & updates); Sibley and Monroe (1990, 1993); Stotz et al. (1996).
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.htm#.
Red List criteria met
Red List history
IUCN Red list criteria met and history
||Does not normally occur in forest
|Land mass type
Land-mass type - continent
Population justification: In Argentina, surveys in southwest Buenos Aires and adjacent areas of La Pampa in 1992-1996 produced an estimated population size of 7,500 individuals (approximately equivalent to 5,000 mature individuals; Tubaro and Gabelli 1993, 1999). Less than 29% of apparently suitable sites were occupied by the species. The species's extent of occurrence was estimated to be approximately 8,000 km2 (Tubaro and Gabelli 1999). More extensive surveys in the same region in 1999 produced a population size estimate of at least 28,000 individuals (approximately equivalent to 18,667 mature individuals) and an extent of occurrence of 4,810km2, indicating a range contraction of c.30% since 1992-1996 (Gabelli et al. 2004). The higher population estimate was attributed to a greater sampling effort than that used in the previous study. More recently, the Argentinian national Red List states that the estimate by Gabelli et al. (2004) was likely an overestimate, and that surveys in 2011-2014 found a population size 10% smaller than that estimated in 1992-1996 (MAyDS and Aves Argentinas 2017), which would equate to a population size of 6,750 individuals, or approximately 4,500 mature individuals. The population in Argentina in 2017 was considered to be smaller than 2,500 mature individuals (MAyDS and Aves Argentinas 2017), but the basis of this figure was not provided. The current population size in Argentina is therefore estimated to fall within the band 4,000-5,000 mature individuals.
In Uruguay, surveys in the Arerunguá region, Salto, and surrounding areas in 2003 estimated a regional population of 78-90 pairs (equivalent to 156-180 mature individuals; Azpiroz 2005). Subsequent studies revised this figure to c.150-200 pairs (equivalent to 300-400 mature individuals) in 2012 (Azpiroz and Cozzani 2017). A further population of 50-70 individuals (equivalent to 33-47 mature individuals) was recently discovered in Tacuarembó (Azpiroz and Cozzani 2017). However, during the 2016 breeding season, only five breeding pairs were recorded in the Arerunguá area, in an area thought to have contained 100-140 pairs in the last decade (Azpiroz and Cozzani 2017). During the 2017 breeding season, 5-20 pairs (approximately equivalent to 10-40 mature individuals), plus a post-breeding group of around 120 individuals (many of which were juveniles) were recorded in the area (Azpiroz and Cozzani 2017). The population size in Uruguay is therefore likely to fall within the band 50-200 mature individuals. The global population size is therefore placed in the range 4,000-6,000 mature individuals.
In Argentina, population densities were estimated to be 50 individuals per km2 (C.I. 20-126) in natural grasslands in the southwest of the surveyed region, and 4 individuals per km2 (C. I. 0.8-22) in the northeast (Gabelli et al. 2004). Surveys of grasslands and cultivated areas in Uruguay in 2004-2005 recorded mean population densities of 13.6 individuals per km2 (C. I. 5.4-34.3) in grasslands grazed by cattle and sheep, and 1.5 individuals per km2 (C. I. 0.4-5.8) in grasslands grazed by cattle and Pampas Deer (Azpiroz and Blake 2009). Pretelli et al. (2013) estimated a density of 5 individuals per km2 of wintering individuals, during surveys of Cortaderia selloana grasslands in the south-east Pampas region, Argentina.
The subpopulations in Bahia Blanca (Argentina) and Arerungua (Uruguay) are around 900 km apart. A study of the species's genetics estimated than an average of 2.57 individuals migrate between the two subpopulations per year, and that the two populations have four genetic clusters: two in the Arerungua population, one in the Bahia Blanca population, and another shared between the two (Repetto 2017). There are therefore considered to be 1-4 subpopulations.
Trend justification: Recent estimates for the population size in Argentina have included: c.7,500 individuals (equivalent to 5,000 mature individuals) in 1992-1996 (Tubaro and Gabelli 1999) and 28,000 individuals (equivalent to 18,667 mature individuals) in 1999 (Gabelli et al. 2004). The species's extent of occurrence in Argentina was also found to have contracted by 30% between 1993-1996 and 1999 (Gabelli et al. 2004), which would equate to a reduction of 55% over ten years. However, the Argentinian Red List (MAyDS and Aves Argentina 2017) states that the 1999 population estimate was an overestimate, and that surveys in 2011-2014 have found a population size 10% smaller than that estimated in 1992-1996, which would approximately equate to 4,500 mature individuals. This rate of decline would equate to a reduction of 5.5% over ten years, assuming the 1992-1995 estimate was accurate, or a 64% reduction over ten years if the 1999 population estimate was correct. The Argentinian Red List also states that the current population in Argentina is less than 2,500 mature individuals, but the basis of this estimate is not described (MAyDS and Aves Argentina 2017).
In the Arerunguá area in Uruguay, there were an estimated 300-400 mature individuals in 2012 (Azpiroz and Cozzani 2017). A further population of 50-70 individuals (equivalent to 33-47 mature individuals) was recently discovered in Tacuarembó (Azpiroz and Cozzani 2017). However, during the 2016 breeding season, only five breeding pairs were recorded in the Arerunguá area, in an area thought to have contained 100-140 pairs in the last decade (Azpiroz and Cozzani 2017). During the 2017 breeding season, 5-20 pairs, plus a post-breeding group of around 120 individuals (many of which were juveniles) were recorded in the area (Azpiroz and Cozzani 2017). Assuming the population size declined from 300-450 mature individuals in 2012, to 50-200 mature individuals in 2017, this rate of decline would equate to a reduction of between 56% and 99% over ten years.
Based on the evidence described, the species is inferred to have undergone an overall reduction of between 9% and 69% across the past ten years, with the best estimate tentatively placed in the band 30-49%. Current trends are assumed to continue over the next decade.
Important Bird and Biodiversity Areas (IBA)
BirdLife International (2021) Species factsheet: Leistes defilippii. Downloaded from
http://www.birdlife.org on 21/10/2021.
Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from
http://www.birdlife.org on 21/10/2021.