The pied kingfisher (Ceryle rudis) is a species of water kingfisher widely distributed across Africa and Asia. Originally described by Carl 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 was one of the many bird species originally described by Linnaeus in the landmark 1758 10th edition of his Systema Naturae, who noted that it lived in Persia and Egypt. He named it Alcedo rudis.[2] The German naturalist Friedrich Boie erected the genus Ceryle in 1828.[3] The name is from classical Greek kērulos, an unidentified and probably mythical bird mentioned by Aristotle and other authors. The specific epithet rudis is Latin for "wild" or "rude".[4]
The pied kingfisher is the only member of the genus Ceryle. Molecular analysis shows it is an early offshoot of the lineage that gave rise to American kingfishers of the genus Chloroceryle.[5] The pied kingfisher was initially believed to be descended from an ancestral American green kingfisher which crossed the Atlantic Ocean about one million years ago.[6] A more recent suggestion is that the pied kingfisher and the American green kingfishers are derived from an Old World species, with the pied kingfisher or its ancestor losing the metallic colouration afterwards.[5]
This is a medium-sized kingfisher, about 25 cm (9.8 in) long with a white with a black mask, a white supercilium and black breast bands. The crest is neat and the upperparts are barred in black. Several subspecies are recognized within the broad distribution. The nominate race is found in sub-Saharan Africa, extending into West Asia. The subspecies syriacus is a larger northern bird similar to the nominate subspecies (following Bergmann's rule).[8] Subspecies leucomelanura is found from Afghanistan east into India, Thailand and Southeast Asia. The subspecies travancoreensis of the Western Ghats is darker with the white reduced. The subspecies C. r. insignis is found in Hainan and southeastern China and has a much larger bill. Males have a narrow second breast-band while females have a single broken breast band.[11][12]
It is common throughout sub-Saharan Africa and southern Asia from Turkey to India to China. It is resident, and most birds do not migrate, other than short-distance seasonal movements.[13] In India it is distributed mainly on the plains and is replaced in the higher hills of the Himalayas by the crested kingfisher (Megaceryle lugubris).[14]
The pied kingfisher is estimated to be one of the three most numerous kingfishers in the world; the other two are the common kingfisher and collared kingfisher. It is a noisy bird, making it hard to miss.[13]