This discussion was first published as part of the 2012 Red List update, but remains open for comment to enable reassessment in 2013.
Streaked Reed-warbler Acrocephalus sorghophilus is poorly known and winters in the Philippines, mostly on Luzon, with records also from Negros and Bohol, where it favours reedbeds and tall rank grassland close to water (Kennerley and Pearson 2010). It is thought to breed in north-eastern China (probably in Hebei, Liaoning, Jilin and Heilongjiang provinces) and adjacent areas of Russia, namely the Amur region, where it potentially uses willow scrub and reedbeds (Kennerley and Pearson 2010).
It is currently listed as Vulnerable under criterion C2a(ii), on the basis that there are thought to be fewer than 10,000 mature individuals in its population, which is regarded as forming one subpopulation, and is inferred to be in continuing decline owing to on-going habitat destruction, at least in its wintering grounds and probably also in its breeding range. Suitable habitat in the Philippines is threatened by conversion to agricultural land, mainly rice fields, and fishponds, industrial development and human settlement. The conversion of wetlands for agricultural use in north-eastern China may also be contributing to the population decline (Kennerley and Pearson 2010).
This species has become less frequent on passage in recent years and concerns have been raised that there may now be fewer than 2,500 mature individuals remaining (D. Allen in litt. 2011). This would qualify the species for uplisting to Endangered under criterion C2a(ii); however, more information is required. Comments are invited on the likely population size and rate of population decline over a period of three generations, estimated by BirdLife to be 13 years (based on an estimated generation length of c.4.4 years). Analyses of trends in the annual number of passage records would be gratefully received, and any other new information on this species would be welcomed.
Kennerley, P. and Pearson, D. (2010) Reed and bush warblers (Helm Identification Guide). London, UK: Christopher Helm.