Widely distributed across southern Asia and Oceania. In Australia, the species inhabits most of the coastline and offshore islands, including the Torres Strait Islands.
Prey items include fish and other small aquatic animals. It will sometimes stand quietly with wings spread to attract fish to the shade and/or reduce glare from the water surface. Prey, when within range, is captured by a sudden jabbing down action.
The species displays an unusual, non-sexual dimorphism, with most individuals possessing charcoal-grey plumage, whilst others have entirely white plumage.