Current view: Data table and detailed info
Taxonomic source(s)
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.
IUCN Red List criteria met and history
Red List criteria met
Red List history
| Migratory status |
full migrant |
Forest dependency |
does not normally occur in forest |
| Land-mass type |
continent
|
Average mass |
- |
Population justification: The population size is very difficult to estimate given the poor quality of historic data and the paucity of recent sightings. In 2016, the population size was set at fewer than 1,000 mature individuals (250-999) based on the paucity of records. This attrition of sightings has continued, with only a single probable record (in 2019) between 2016 and 2021. The population may therefore now be very small (<50 mature individuals), although there remains substantial uncertainty in this inference given the lack of surveys on its (thus far undiscovered) breeding grounds. The population is therefore suspected to number 1-999, although it is acknowledged that this represents little more than a best guess.
Trend justification: The trends of this species are poorly known due to the very few recent records, but it appears clear that the population has declined rapidly over the past few decades. The breeding grounds remain wholly unknown, such that trends can be derived only from the passage and non-breeding parts of its range. On passage in north-east China (in and around Beijing), the species has declined substantially since La Touche (1920) described it as "very common every early autumn" near Qinghuangdao (Hebei). There were several scattered sightings between 2005 and 2015: Peking University campus, September 2007; Yuanmingyuan, Haidian, September 2008; Wild Duck Lake, October 2008; Summer Palace, Haidian, June 2009; Olympic Forest Park, May 2011; Yanqing, June 2014; Dayunhe Forest Park, Tongzhou, September 2014; Liaotieshan, Dalian, Liaoning, September 2015 (T. Townshend in litt. 2021). Since then, there has been only a single probable (and undocumented) record—of an individual at the Shunyi Patch on 6 October 2019—despite greatly increased coverage of the region by birdwatchers over the past decade (T. Townshend in litt. 2021).
In the Philippines (its only known wintering area), this attrition of sightings and abundance has been mirrored. At Dalton Pass, Luzon, 351 individuals were ringed on passage in 1965-1970, with yearly maxima of 141 in 1965 and 127 in 1966 (McClure and Leelavit 1972) and several birdwatchers and ornithologists recorded multiple individuals—and did not regard it as especially uncommon—on Luzon in the 1980s and 1990s (Collar et al. 1999). Since then, a precipitous decline has seemingly ensued, thought to have principally been caused by habitat degradation and destruction (Collar et al. 1999, BirdLife International 2001). There have been no confirmed sightings in the Philippines since the ringing of an individual at Candaba Swamp (the only known wintering site) in 2009 among 123 Acrocephalus warblers (Round and Allen 2010), despite increased visitation by birdwatchers (eBird 2021).
Based on historic records of passage the breeding grounds are assumed to lie in north-east China (Kennerley and Pearson 2010) however a targeted search for Acrocephalus and Locustella warblers in 2019 in a hitherto unsurveyed area in northern Jilin and Heilongjiang failed to detect the species at all, despite this area being considered a prime candidate for its discovery (with a climate that well matches the species' unusually late migration phenology; see Townshend 2019) and surveyors covering a range of feasible habitats over 31 days. They detected (and therefore identified new sites for) other poorly known species including A. tangorum and L. pryeri (Guillaumet et al. 2021). A single sighting of a singing A. sorghophilus along the Amur River, Russia, in 2004 has not been replicated, despite a return to the same area in 2007 (Kennerley and Pearson 2010).
Given these trends in spite of increased coverage, the population is suspected to have declined rapidly (80-99%) over the past ten years and it is not definite that the a population of the species even persists, although further surveys across north-east China at likely localities is needed.
Country/territory distribution
Important Bird and Biodiversity Areas (IBA)
Recommended citation
BirdLife International (2024) Species factsheet: Streaked Reed-warbler Acrocephalus sorghophilus. Downloaded from
https://datazone.birdlife.org/species/factsheet/streaked-reed-warbler-acrocephalus-sorghophilus on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/12/2024.
