This discussion was first published as part of the 2013 Red List update, but remains open for comment to enable reassessment in 2014.
Chilean Woodstar Eulidia yarrellii is only known to breed regularly in the Azapa and Vitor valleys, Arica department, extreme north Chile (Estades 2007). It is currently listed as Endangered under criterion B1ab(i,ii,iii,v) because it has a very small range (estimated Extent of Occurrence [EOO]=2,200 km2) with all viable populations apparently confined to remnant habitat patches in two desert river valleys (Collar et al. 1992). As these valleys are heavily cultivated, the extent, area and quality of suitable habitat (and therefore the population) are likely to be declining.
Surveys since 2003 have failed to find this species in the Lluta valley where it had previously been recorded in small numbers (Estades 2007). Stragglers have been found north to Tacna and possibly Moquegua departments, south Peru, and there is a historical record as far south as north Antofagasta province, but there are no recent records for Peru (Estades 2007). It was described as very common in the first half of the 20th century, with over 100 seen feeding together. In 2003 the Azapa valley held around 75 % of the total population, which was estimated at around 1,500 individuals (Estades 2007), while in 2007 the total population was estimated at around 1,200 individuals (55% in Azapa and 45% in Vitor) (C. Estades in litt. 2007). Recent information suggests that the population of this species has now greatly declined to ~500 individuals (D. Lebbin in litt. 2012). Also, the rate of decline is more rapid than previously thought; population estimates have shown that the Azapa and Vitor populations have reduced by 15.6% annually (81.6%) in 10 years (C. F. Estades in litt. 2013). If there is sufficient evidence to suggest that the global population of this species has declined by ≥80% over the past three generations (13 years), and similar declines are suspected in the future based on a decline in area of occupancy, extent of occurrence, and/or quality of habitat, it would warrant uplisting to Critically Endangered under criteria A2c+3c+4c of the IUCN Red List. Should evidence suggest that the rate of decline is 50-79% over 13 years, and given that its EOO is <5,000 km2, it is found at ≤5 locations and is in continuing decline, this species would remain as Endangered under criteria A2c+3c+4c; B1ab(i,ii,iii,v).
Further information is requested on the population trends, size and distribution of this species. Comments on the proposed uplisting are welcome.
Collar, N. J., Gonzaga, L. P., Krabbe, N., Madroño Nieto, A., Naranjo, L. G., Parker, T. A. and Wege, D. C. (1992) Threatened birds of the Americas: the ICBP/IUCN Red Data Book. International Council for Bird Preservation: Cambridge, U.K.
Estades, C. F., Aguirre, J., Escobar, M. A. H., Tomasevic, J. A., Vukasovic, M. A. and Tala, C. (2007) Conservation status of the Chilean woodstar Eulidia yarrellii. Bird Conservation International 17(2): 163-175.