This species is marine. It mainly occurs over continental shelves and slopes, and occasionally in inshore waters. There is no information available about its diet in the UAE; elsewhere, generally it feeds mostly on fish and squid, but also on marine invertebrates, which it takes by pursuit-plunging (Carboneras et al. 2019).

It frequents open sea all-year-round, only approaching land during the breeding season, at dusk and after dark (Taleb 2002, PERSGA/GEF 2003). Its foraging areas are poorly known, but presumably related to highly productive areas of oceanic upwelling (PERSGA/GEF 2003). It flies low, taking food from the surface of sea, probably mainly plankton e.g. fish eggs, ctenophores and polychaete worms (PERSGA/GEF 2003).

This species inhabits inland wetlands including rivers, freshwater and brackish lakes, densely vegetated marshes, reservoirs, irrigation ponds and sewage treatment plants (Richardson 1990, Jennings 2010, Aspinall and Porter 2011). During migration, it may also be found in wadis (Richardson 1990). Its diet in the UAE is not well known; elsewhere it is an opportunistic feeder taking fish, frogs, tadpoles, turtles, snakes, lizards, insects, spiders, crustaceans, molluscs, leeches, small rodents, bats and the eggs and chicks of other bird species (del Hoyo et al. 1992, Kushlan and Hancock 2005). The species is largely crepuscular and nocturnal, but may feed diurnally, especially during the breeding season (del Hoyo et al. 1992). It breeds during mid to late summer; nesting sites may be used in consecutive years (Jennings 2010). There is not much known about its breeding biology in the UAE or in Arabia. Usually, the nest is platform constructed of sticks and vegetation placed 2-50 m above water or on dry ground near water in trees, bushes, reedbeds, on cliff ledges and on the ground in protected sites (del Hoyo et al. 1992, Snow and Perrins 1998, Kushlan and Hancock 2005). The species nests close together in single- and mixed-species colonies (del Hoyo et al. 1992).

This species is almost entirely pelagic and only comes ashore to breed. It forages solitarily (Jennings. 2010). There is no information available about its diet in the UAE; elsewhere it feeds primarily on small fish, especially flying fish, but will also take squid. Most prey is caught by plunge-diving, but flying-fish are sometimes taken in flight (del Hoyo et al. 1992). It breeds colonially on rocky cliffs or slopes on islands, and only very rarely on the mainland (Aspinall and Porter 2011). There is no nest produced from any materials; instead, one egg is laid directly on the bare sand, stone or rock. In Arabia, the species generally nests in long, natural rock cavities with only one entrance, in caves or under overhangs in areas which are free of vegetation (Jennings 2010). The species's breeding biology in the Arabian Gulf is not well known. Birds return to their breeding sites in October and November, with eggs being recorded between December and June. It has been suggested that late breeding records come from inexperienced, young breeders using low-quality nesting sites (Jennings 2010). Breeding colonies are abandoned after breeding when individuals disperse over large distances; radio-tracking revealed that bird breeding on Qarnyan Island travelled to the Kerala coast of India (Jennings 2010).

This species is found near coastal wetlands during winter, e.g. in mangroves, on inshore islands, in lagoons and mudflats (Richardson 1990, Aspinall and Porter 2011), it may also occur in agricultural areas (e.g. fodder fields and plantations). On passage, the species also occurs in wetlands further inland, such as marshes, but also near rubbish dumps (Richardson 1990). There is no information available on its diet in the UAE; elsewhere it feeds on unretrieved quarry, small mammals, waterbirds, frogs and snakes, hunting over swamps, wet meadows and over agricultural land(A. Làµhmus in litt. 1999); birds soar to c.100 m high when hunting. It is a migratory species. Birds breeding in central Asia winter in the UAE or migrate further south along the Arabian Peninsula until north-east Africa (del Hoyo et al. 1994). The species arrives at the non-breeding grounds in September and leaves again between February and April (Pedersen et al. 2017). The species migrates on a broad front, tending to pass in singles, twos and threes with the occasional larger group (Ferguson-Lees and Christie 2001). Individuals do not concentrate at bottleneck sites to the extent of many other raptors, such as Lesser Spotted Eagle Clanga pomarina (del Hoyo et al. 1994).

This species is found in open habitat, favouring steppe, grassland, agricultural fields and sandy desert (Aspinall and Porter 2011). The species is migratory, with most birds wintering in sub-Saharan Africa or south-east Asia. Birds occur in the UAE between September and March, occasionally until April, and mainly breed in the steppes of southern Russia (Richardson 1990). Birds migrate on a broad front, with only minor concentrations at bottleneck sites (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001). Although birds are most often seen singly, females and juveniles can form parties of 10-15 individuals on migration (Snow and Perrins 1998, Ferguson-Lees and Christie 2001). Birds fly at c.1-9 m above the ground when hunting (del Hoyo et al. 1994, Snow and Perrins 1998) and fly generally higher on migration, but tend to remain from c.1-15 m above the ground (Brown et al. 1982).

This species inhabits coastal zones like mudflats, coral reefs, mangroves and sheltered lagoons, but never occurs inland (Richardson 1990, Aspinall and Porter 2011). Breeding colonies are situated on sandbanks and islets low above the high tide mark or on sandy dunes (Hayman et al. 1986, del Hoyo et al. 1996, Jennings 2010). Outside of the breeding season, the species is found on open mudflats, sometimes in proximity to mangroves (Jennings 2010). During passage, it also occurs along creeks (Richardson 1990). Its diet consists predominantly (> 95%) of crabs and occasionally of small fish (del Hoyo et al. 1996, Jennings 2010). The species forages nocturnally mostly under semi-closed mangroves (Avicennia marina), but occasionally also on open intertidal flats (Jennings 2010). The breeding season starts in May, when nesting tunnels and burrows are excavated in moist sand (Jennings 2010, Aspinall and Porter 2011). These tunnels can be more than 2 m long and lead up to 1 m below the surface (del Hoyo et al. 1996, Jennings 2010). There is no other nesting material used (Jennings 2010). Clutches contain only one egg (Jennings 2010). Chicks hatch by mid-June and fledge in August (Jennings 2010). Juveniles remain with their parents for several months, including on the wintering grounds (Jennings 2010). The migratory movements are poorly understood. Individuals from the breeding colonies on Umm Amim and Abu al-Abyadh islands may disperse after the breeding season locally in response to food availability (Jennings 2010). However, individuals may also migrate southwards between August and November; one satellite-tagged bird from the UAE was found to winter in the Seychelles (Javed et al. 2011), while others may move to the East African coast or the eastern Indian Ocean (Jennings 2010). These individuals return northwards between March and April, although over much of its range the species is present in fluctuating numbers throughout the year (Hayman et al. 1986).

During the breeding season, this species inhabits eutrophic freshwater sites like marshes with effluent water input or nearby rubbish dumps, as well as pools with bare mud areas or tall reed beds (Jennings 2010, Aspinall and Porter 2011). During the non-breeding season, it prefers shallow coastal lagoons. During migration, it may be found at any type of freshwater body, including temporary rain pools, sewage lagoons, brackish coastal pools and tidal ponds (Jennings 2010). Its diet consists mainly of insects, but also of worms, molluscs and crustaceans, which it takes from soft mud and in shallow water (del Hoyo et al. 1996, Jennings 2010). At the beginning of the breeding season in February, the species establishes territories in loose colonies (Hayman et al. 1986, del Hoyo et al. 1996, Jennings 2010). The nest is a shallow scrape, lined with small sticks, stones or shells (del Hoyo et al. 1996, Jennings 2010). It is placed in muddy areas or close to bushes near water (del Hoyo et al. 1996, Jennings 2010). Eggs are laid between March and May (Jennings 2010). The species is partially migratory (del Hoyo et al. 1996). The migrant population in the UAE breeds in central Asia from Turkey to Pakistan and moves south during the non-breeding season, with parts of the population migrating further south to the eastern Sahel in Africa (Jennings 2010). Outside of the breeding season, the species occurs singly, in pairs or small groups, with small migratory flocks of 1-6 individuals and wintering flocks of 6-25 individuals (Urban et al. 1986, del Hoyo et al. 1996).

The breeding population is restricted to open, swampy habitats like shallow waste water sites with rich invertebrate life (Jennings 2010). During migration, the species occurs at any kind of wetland on the coast or further inland, while wintering birds are usually found at shallow, sheltered coastal waters like brackish lagoons (Jennings 2010). Densely vegetated wetlands are not suitable as habitat nor as a foraging site (Jennings 2010). There is no information available about its diet in the UAE or in Arabia; elsewhere it feeds on aquatic invertebrates like insects and larvae, but also worms, crustaceans and occasionally fish, which are taken by scything the bill through the water while walking forward (Jennings 2010). The breeding season lasts from April until July (Jennings 2010). The species nests colonially on small islands in low vegetation near shallow water (Jennings 2010, Aspinall and Porter 2011). The nest is usually a scrape, sometimes with a raised rim and lined with plant material, which may be positioned in a variety of sites including on bare sand and dried mud (Johnsgard 1981, del Hoyo et al. 1996, Jennings 2010). Clutches contain three to four, sometimes up to six eggs (Jennings 2010). The species is partly migratory. Individuals wintering in the UAE or passing through the country on migration breed in central Eurasia (Jennings 2010). It is unclear whether the breeding population in Arabia is resident or if it migrates southward after breeding, to be replaced by wintering migrants from northern breeding grounds (Jennings 2010).

This species occurs mainly in coastal mudflats and tidal pools, but also in shallow fresh and brackish water and in wetlands further inland (Richardson 1990, del Hoyo et al. 1996, Aspinall and Porter 2011). There is no information available about its diet in the UAE; elsewhere it is omnivorous and feeds mainly on marine nereid worms, small bivalves and snails, crustaceans, insects, as well as the seeds of aquatic plants (del Hoyo et al. 1996, Snow and Perrins 1998). The species is migratory. Birds wintering in the UAE breed in June in wet lowlands of subarctic Scandinavia (Richardson 1990, del Hoyo et al. 1996). Individuals leave the breeding grounds by July, and stop-over in substantial numbers in Sivash (southern Ukraine) and on the Caspian Sea or the Bulgarian seaboard, before arriving in wintering grounds in late July and August (Richardson 1990, del Hoyo et al. 1996). The species migrates singly or in small groups, although during the spring migration flocks of up to several hundred can occur (del Hoyo et al. 1996). The population departs the wintering grounds in spring in April or May (Richardson 1990, del Hoyo et al. 1996).A few non-breeding birds remain at the wintering sites during the summer (del Hoyo et al. 1996, Pedersen et al. 2017).