The pied kingfisher (Ceryle rudis) is a species of water kingfisher widely distributed across Africa and Asia. Originally described by Linnaeus in 1758, it has five recognised subspecies. Its black and white plumage and crest, as well as its habit of hovering over clear lakes and rivers before diving for fish, make it distinctive. Males have a double band across the breast, while females have a single gorget that is often broken in the middle. They are usually found in pairs or small family groups. When perched, they often bob their head and flick up their tail.The pied kingfisher is estimated to be one of the three most numerous kingfishers in the world.
When perched the pied kingfisher often bobs its heads up and down and will sometimes raise its tail and flick it downwards. It calls often with sharp chirruk chirruk notes. Unlike some kingfishers, it is quite gregarious, and forms large roosts at night. This kingfisher feeds mainly on fish, although it will take crustaceans and large aquatic insects such as dragonfly larvae. It usually hunts by hovering over the water to detect prey and diving vertically bill-first to capture fish. When not foraging, it has a straight rapid flight and have been observed flying at nearly 50 km/h. In Lake Victoria in East Africa the introduction of the Nile perch reduced the availability of haplochromine cichlids which were formerly the preferred prey of these birds.
It can deal with prey without returning to a perch, often swallowing small prey in flight, and so can hunt over large water bodies or in estuaries that lack perches that are required by other kingfishers.
Source : Wikipedia