ON THE BACK: Only the female kingfisher has a red lower bill. Kingfisher numbers plummet in very cold winters and summers with bad flooding but in good years numbers can soon recover with two or three broods of six or seven eggs. The vivid blue and cyan colours of the kingfisher are not produced by a pigment - the feathers have no pigment but are transparent. Specific wavelengths of light are reflected from differing nanostructures in the feathers producing the iridescent blue colouration.