This discussion was first published as part of the 2012 Red List update, but remains open for comment to enable reassessment in 2015.
Northern Screamer Chauna chavaria is endemic to the marshlands of northern Colombia and north-western Venezuela. It is currently listed as Near Threatened under criterion C2a(i) on the basis that its global population is thought to number fewer than 10,000 individuals and suspected to be declining as a result of hunting and habitat conversion; however, so far there has been insufficient information available on its sub-population structure for it to qualify as Vulnerable. It is listed as Vulnerable at the national level in the two countries in which it occurs, and may qualify as globally threatened. To confirm whether this is the case, more information is required, particularly on its status in Colombia, where the majority of the world population is found.
The Colombian sub-populations are variously calculated to amount to between 2,000 and 10,000 birds (Renjifo et al. 2002), with most recent estimates suggesting at least 5,000 (P. G. W. Salaman in litt. 1999). However, the species’s Area of Occupancy is fragmented, within a potential area of habitat of 8,900km2 (Renjifo et al. 2002). Its national status is currently Vulnerable under criterion C2a(i) because its small population is thought to be in decline owing to hunting and habitat conversion (Renjifo et al. 2002). Current assessments of the status of the Colombian sub-populations would be welcome.
The Venezuelan sub-population, confined to the southern Lake Maracaibo basin (Extent of Occurrence [EOO] of less than 30,000km2), is crudely estimated at fewer than 2,000 birds, and is thought to be in decline owing to hunting and the conversion of wetlands to cattle pasture (C. J. Sharpe unpubl.). The draft national threat category was therefore Endangered under criterion C2a(ii) (C. J. Sharpe unpubl.), as amended to Vulnerable under C2a(ii) in the most recent national assessment (Rodríguez and Rojas-Suárez 2008). More information is required on the national sub-population, trends and threats.
In order to reassess the status of this species, we would welcome comments on: a) recent declines, which might lead to the reclassification as Vulnerable under C1 if the decline is thought to be at least10% over 15 years (estimate of three generations; BirdLife International unpubl. data), and b) sub-population figures, which might result in the same categorisation under C2a(i) (should the largest sub-population be fewer than 1,000 individuals).
Renjifo, L. M., Franco-Maya, A. M., Amaya-Espinel, J. D., Kattan, G. H. and López-Lanús, B. (2002) Libro rojo de aves de Colombia. Bogotá, Colombia: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt y Ministerio del Medio Ambiente.
Rodríguez, J. P. and Rojas-Suárez, F. (eds) (2008) Libro Rojo de la Fauna Venezolana. Third Edition. Caracas, Venezuela: Provita and Shell Venezuela, S.A.