It inhabits freshwater marshes, lakes, rivers, flooded grasslands, paddy fields, tidal creeks, intertidal mudflats, mangroves, saltmarshes and coastal lagoons, usually in coastal wetlands or extreme lowlands, but occasionally up to 950 m. In some areas, agricultural land may be an important habitat for the species (Sundar 2009, Sundar and Kittur 2013, G. Sundar in litt. 2024). It is largely sedentary throughout most of its range but tends to be nomadic in response to changing water levels and feeding conditions (Matheu et al. 2016).

Resident across virtually all of India and Sri Lanka, marginally also in south-east Pakistan. Occurs in the Himalayan foothills of Nepal and very locally Bhutan (where there are records from the upper reaches of the Manas River: eBird 2024), as well as Bangladesh. Occurs throughout suitable habitat in Myanmar. Status in China and Japan unclear, but treated here as a vagrant given paucity of recent records, but may be better considered a very rare non-breeding visitor. Occurs in central Thailand (particularly in wetlands around Bangkok north to Nakhon Sawan) with records increasingly further north in response to increasing populations. Vagrants have also reached the Philippines. Throughout wetlands of Cambodia and southern Viet Nam, but puzzlingly absent from Lao PDR, where remains known from only a single historical record (Duckworth et al. 1999, Timmins et al. 2024). Scattered records from northern Viet Nam, particularly from Xuan Thuy National Park, but here probably only a vagrant or very sporadic non-breeding visitor. Occurs regularly as far south as Phatthalung province, southern Thailand, but sporadic records stretch south into Peninsular Malaysia where it was once more regular than it is now. Vagrant to Singapore, where sporadic records (especially at Sungei Buloh Wetland Reserve). Range and abundance in Indonesia poorly known, but evidently still regular at least in south-east Sumatra and westernmost Java (around Jakarta).