In the Palearctic this species is migratory and dispersive (Billerman et al. 2020), travelling on a broad front between breeding and wintering areas (Kushlan and Hancock 2005). The species breeds from April to July in Eurasia in single- or mixed-species colonies that can be up to 2,000 pairs in size. After breeding Palearctic populations migrate south from August to November (Kushlan and Hancock 2005, Billerman et al. 2020), returning to the breeding colonies between February and May (Kushlan and Hancock 2005). The species feeds solitarily (Kushlan and Hancock 2005) or in small groups of 2–5 individuals during the breeding season (Kushlan and Hancock 2005) although in winter and on migration large feeding flocks may form (Kushlan and Hancock 2005). The species is mainly crepuscular (Billerman et al. 2020), roosting by day and night in large (Kushlan and Hancock 2005) often mixed-species (Brown et al. 1982) groups in sheltered woods and reedbeds (these roosts may draw in herons feeding up to 80 km away) (Kushlan and Hancock 2005). The species inhabits permanent or temporary wetlands (Brown et al. 1982) showing a preference for fresh waters with abundant marsh vegetation (Billerman et al. 2020), reedbeds, nearby bushes, trees and scrub (Kushlan and Hancock 2005). Habitats frequented include swampy plains, river valleys, deltas, lakes, ponds, canals, ditches and rice paddyfields (Billerman et al. 2020). On migration (Kushlan and Hancock 2005) the species may also occur on estuaries, inshore reefs or islets (Billerman et al. 2020). It generally avoids dry habitats and those with very high rainfall (Kushlan and Hancock 2005), and usually breeds in the lowlands although it has bred on montane lakes up to 2,000 m. Its diet consists predominantly of larval insects although fish and amphibians (Billerman et al. 2020) (e.g. frogs and tadpoles) (Kushlan and Hancock 2005) up to 10 cm long, grasshoppers, beetles, butterflies, spiders, crustaceans, molluscs and exceptionally small birds may also be taken. The nest is a well-constructed platform usually placed less than two metres (occasionally up to 20 m) high near or over water in reedbeds (Billerman et al. 2020) or in dense thickets of trees or shrubs (Kushlan and Hancock 2005) (e.g. of willow (Salix spp.) or poplar (Populus spp.)) (Hafner and Didner 1997), preferring nesting sites within five kilometres of feeding areas (Kushlan and Hancock 2005). The species breeds in single- or mixed-species colonies that can be up to 2,000 pairs in size (Billerman et al. 2020), neighbouring pairs building nests 5–10 m apart (occasionally as close as 0.5 m) (Kushlan and Hancock 2005).

Although the generation length for both EU and Europe regional assessments were calculated using the same methodology, new information arriving after the EU assessments were undertaken gave rise to an update in the generation lengths. This new information was then used for the Europe level assessments giving rise to a difference between the generation lengths used for the EU and Europe regions.

In Europe, this species breeds notably in Azerbaijan, Russia, Romania, Turkey, Spain and Ukraine.

Conservation Actions Underway
The species is listed on Annex I of the EU Birds Directive, Annex II of the Bern Convention and Annex II of the Convention on Migratory Species, under which it is covered by the African-Eurasian Waterbird Agreement (AEWA).

Conservation Actions Proposed
Reed marshes and freshwater habitats need to be sustainably managed, including the reduction of water pollution and fish overexploitation.