Most Palearctic populations of this species are fully migratory, dispersing widely in September and October after the breeding season and returning to breeding grounds in February (Kushlan and Hancock 2005). This species is a generalist in its habitat use, although shallow water, relatively large prey, and four or five months of ice-free breeding season are among the essential characteristics of its habitat (Kushlan and Hancock 2005). It occurs from sea-level up to 500 or even 1,000 m, occasionally breeding much higher (Snow and Perrins 1998) (2,000 m in Armenia), inhabits any kind of shallow water, either fresh, brackish or saline, both standing or flowing, and shows a preference for areas with trees as it is commonly an arboreal rooster and nester. Some degree of isolation and protection are also typical of places chosen for roosting and nesting (Kushlan and Hancock 2005). The species is found inland on broad rivers, narrow streams, lake shores, ornamental ponds, fish-ponds, marshes, flood-plains, reeds swamps, rice-fields and other irrigated areas (Brown et al. 1982, Snow and Perrins 1998, Kushlan and Hancock 2005), river oxbows, reservoirs, ditches, canals, sewage farms, inland deltas, and on islets and emerging rocks (Snow and Perrins 1998). On the coast the species also frequents deltas, salt-marshes (Brown et al. 1982, Kushlan and Hancock 2005), estuaries, tidal mudflats, muddy and sandy shores, and sand-spits (Snow and Perrins 1998). Its diet consists predominantly of fish and eels 10–25 cm long, as well as amphibians, crabs, molluscs, crustaceans, aquatic insects, snakes, small rodents, small birds (Brown et al. 1982, Snow and Perrins 1998, Kushlan and Hancock 2005) and plant matter (although this may be incidental, or only to aid in pellet formation) (Brown et al. 1982, Snow and Perrins 1998, Kushlan and Hancock 2005). The nest is a stick platform that is often re-used over successive years (Kushlan and Hancock 2005), usually positioned high in a tall tree up to 50 m, but also on the ground or on cliff edges, in reedbeds or in bushes. In reed-beds nests may be built of reeds, and ground nests may be reduced to a slight scrape, ringed with small stones and debris (Snow and Perrins 1998). The species commonly nests in colonies and nesting sites are typically situated 2–38 km (convenient flying distance) from preferred feeding areas (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 in most countries, notably in Russia, Ukraine, France and Germany.

Conservation Actions Underway
The species is not listed on priority lists of the Conventions.

Conservation Actions Proposed
Freshwater habitats need to be sustainably managed. Establish non-intrusion zones and stop logging around colonies.