the pied kingfisher (ceryle rudis) is a water kingfisher and is found widely distributed across africa and asia .
their black and white plumage , crest and the habit of hovering over clear lakes and rivers before diving for fish makes 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 parties .
when perched , they often bob their head and flick up their tail .
this kingfisher is about 17 cm long and is 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 .
a former subspecies syriaca is considered as merely a larger northern bird of the nominate species (following bergmann's rule) .
subspecies leucomelanura is found from afghanistan east into india , sri lanka , thailand and laos .
the subspecies travancoreensis of the western ghats is darker with the white reduced .
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 .
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 .
in india it is distributed mainly on the plains and is replaced in the higher hills of the himalayas by megaceryle lugubris .
the pied kingfisher is estimated to be the world's third most common kingfisher , and being a noisy bird , hard to miss .
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 down bill-first to capture fish .
when not foraging , they have a straight rapid flight and have been observed flying at nearly 32 mph .
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 .
they 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 .
unlike some kingfishers , it is quite gregarious , and forms large roosts at night .
when perched , the often bob their heads up and down and will sometimes raise their tail and flick it downwards .
they call often with sharp chirruk chirruk notes .
the breeding season is february to april .
its nest is a hole excavated in a vertical mud bank about five feet above water .
the nest tunnel is 4 to 5 feet deep and ends in a chamber .
several birds may nest in the same vicinity .
the usual clutch is 3-6 white eggs .
the pied kingfisher sometimes reproduces co-operatively , with young non-breeding birds from an earlier brood assisting parents or even unrelated older birds .
in india , nestings have been found to be prone to maggot infestations (probably by protocalliphora sp .
) and in some areas to leeches .
nest holes may sometimes be used for roosting .
this species was initially believed to be descended from an ancestral american green kingfisher which crossed the atlantic ocean about 1 million years ago .
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 .
in 1947, h b cott noticed while skinning birds that hornets were attracted to certain birds but avoided the flesh of pied kingfishers .
this led to a comparative study of edibility of birds and he suggested that more conspicuously plumaged birds may be less palatable .
this suggestion was , however , not supported by a subsequent reanalysis of his data .
