Fulica atra  

Behaviour Most populations in warm and temperate regions are resident¹, often making nomadic dispersive movements according to changing water levels and seasonal rainfall^{1, 4}.Populations in northern Eurasia are fully migratory however, migrating on a broad front through continental Europe and across the Sahara². Southward movements occur from mid-August to November², with the return passage occurring from late-February² to May¹. The species nests in dispersed solitary pairs^{1, 3, 4}, although it is largely gregarious¹ with flocks (sometimes of several thousand individuals³) frequently forming during the winter^{2, 3, 4}. Adults undergo a post-breeding flightless moult period, with flocks of moulting birds congregating from June-September^{1, 2, 3}. The species is diurnally active and roosts at sunset solitarily or in flocks². It may feed in flocks on land, especially when winds cause high waves on water¹. Habitat The species inhabits large, still or slow-flowing waters^{1, 3} and shows a preference for shallow water with adjacent deeper water (e.g. > 2 m) for diving², and muddy substrates, marginal, emergent, floating or submergent vegetation^{1, 2, 3}. Habitats include eutrophic and mesotrophic² lakes^{1, 3}, pools, ponds, reservoirs, barrages, gravel-pits, canals, drainage ditches, dykes, oxbow lakes^{1, 2, 3}, fish ponds⁷, creeks^{1, 2}, rivers¹ and river deltas², as well as open marshes^{1, 2}, freshwater meadows², flood-lands^{1, 2, 3}, freshwater and saline lagoons⁴, salt-pans, clay-pans^{1, 2} and sewage ponds². It frequently exploits temporary pools and seasonally inundated marshes when breeding (Africa)⁴, and may extend to quiet estuaries or inshore waters in the winter¹. It generally avoids closely overgrown, narrowly confined and very shallow waters, and those overshadowed by trees or cliffs². If solitary the species roosts at sunset on small islets, mudbanks, sandbanks, rocks in water, floating mats of vegetation, floating logs, or branches of trees over water, preferring to roost on open water, in shore vegetation or in meadows adjacent to water if in flocks². Diet This species is omnivorous, although its diet consists primarily of vegetable matter¹ such as algae (e.g. Chara, Cladophora, Spirogyra), the vegetative pasts of aquatic and terrestrial plants (e.g. waterweeds, bulrushes, reeds and grasses), the seeds of waterweeds, sedges, water-lilies, grasses and cereal crops¹, clubmoss Selaginella and aquatic fungi (e.g. Leptomitus)². Animal matter in its diet includes molluscs, adult and larval insects (especially flies, caddisflies, Odonata, Lepidoptera, beetles and bugs)^{1, 2}, worms, leeches, shrimps, spiders¹, small fish^{1, 4}, fish eggs, frogs, birds and bird eggs, and small mammals¹. Breeding site The nest is a platform of vegetation that may be resting on the bottom of shallow water, floating or on a foundation of trampled plant matter in emergent vegetation¹. The species may also nest on artificial platforms, islands, rafts, tree stumps, tree forks¹ or in bushes up to 3 m above the water². Management information A study in the Czech Republic found that fish ponds with a fish stock density of less than 400 kg/ha, water transparency of more than 50 cm, mixed fish stocks (e.g. tench and pike or perch) rather than monospecific stocks (e.g. of carp), and systems that include ponds with fish fry (to provide areas with low fish competition and high invertebrate availability) are more successful in supporting breeding pairs of this species⁷. The cyclical removal of adult fish from an artificial waterbody (gravel pit) in the UK (leaving small fish for piscivorous birds) resulted in increased winter use of the habitat by the species as result of an increase in the growth of submerged aquatic macrophytes¹⁵. The removed fish (dead or alive) were sold to generate funds¹⁵.