Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
In Europe, the breeding population is estimated to number 2,180,000-4,780,000 pairs, which equates to 4,360,000-9,560,000 mature individuals (BirdLife International 2015). Europe forms c.20% of the global range, so a very preliminary estimate of the global population size is 21,800,000-47,800,000 mature individuals, although further validation of this estimate is needed.
The population is suspected to be increasing due to a range expansion in the west of its range. The European population is estimated to be increasing (BirdLife International 2015).
This species has adapted to varied habitats and is not necessarily found close to water; it is more arboreal than most members of the genus (Dyrcz 2006). It breeds in a wide range of shrubby growth with tall herbage, young forests, overgrown clearings, birch (Betula) and willow (Salix) scrub in floodland groves, forest steppes, bush-encroached farmland and swamp and other waterside margins (Hagemeijer and Blair 1997). The breeding season is from the end of May to July. It lays three to six eggs is a nest, which is a neat and compact cup of dry grass stalks and leaves, rootlets, plant fibres, spider web, lined with finer stems and hair and suspended 10–150 cm above ground in a dense herbaceous layer, or sometimes in a shrub or small tree. It feeds mainly on insects but also consumes spiders (Araneae), harvestmen (Opiliones), snails and occasionally seeds. The species is migratory and the entire population winters in the Indian Subcontinent (Nepal, Bangladesh, southern and eastern India and Sri Lanka) and Myanmar (Dyrcz 2006).
There are not thought to be any current significant threats to this species.
Conservation Actions Underway
CMS Appendix II. Bern Convention Appendix II. There are currently no known conservation measures for this species within Europe.
Conservation Actions Proposed
No conservation measures are currently needed for this species within its European range.
Text account compilers
Martin, R, Butchart, S., Ashpole, J, Ekstrom, J.
BirdLife International (2020) Species factsheet: Acrocephalus dumetorum. Downloaded from http://www.birdlife.org on 14/07/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 14/07/2020.