Acrocephalus dumetorum is a widespread summer visitor to central Russia and adjoining areas of northern and central Europe, which accounts for less than half of its global breeding range. Its European breeding population is very large (>2,000,000 pairs), and was stable between 1970-1990. The stronghold population in Russia remained stable during 1990-2000, with trends also stable or increasing elsewhere in Europe, and consequently the species is evaluated as Secure.

Has recently spread west across west Palearctic in upper middle continental latitudes through temperate zone to margin of boreal zone. Although found in willow and alder beds along brooks and rivulets, along canals and irrigation ditches overgrown with reeds and tall grass, at edges of marshes, and occasionally along taiga brooks in thick reedbeds, such aquatic habitats play much less important role than drier and more wooded ones.

Breeds June-July in Finland and West Siberia. Nest site built in dense vegetation including reeds, nettles, shrubs, and small trees. Nest is a neat and compact cup, sometimes conical, of leaves, stems, and plant down, often with spiders' webs, lined finer stems and hair. 3-6 eggs are laid, incubation 12-14 days by both sexes, mainly by female.

Principally insects, also spiders and snails. Feeds by moving about actively in tree canopy and in shrub and herb layer. Quite often also on ground, takes insects in flight.

This species has a large range, with an estimated global extent of occurrence of 10,000,000 km2. It has a large global population, including an estimated 4,000,000-10,000,000 individuals in Europe (BirdLife International in prep.). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.

Common and widespread summer migrant of Eurasia, from southern Finland east across Northwest and central Russia to central Siberia and Northwest Mongolia, and southern U.S.S.R., northern Afghanistan and Southwest Siberia. Winters in subtropical to tropical zones of Pakistan, India, Nepal, Sri Lanka, and east to Burma. (Baker K 1997) Summer visitor Finland, Baltic republics USSR, northern European USSR; winters Indian sub-continent. Scarce migrant/vagrant Sweden (? Regular breeder in east). Vagrant UK (14), Eire (1), Gibraltar, France (1), Denmark (8), Norway (6), Germany (2), Poland (>10), Italy (1), Romania, Cyprus, Syria (1), Kuwait, Jordan, Israel (1). (Parmenter T Byers C 1991)