Coloured scanning electron micrograph (SEM) of the opercular bone from a fish skull. Recovered from Kingfisher (Alcedo atthis) faeces.Bones and other indigestible material, such as eye lenses, from swallowed fish pass through the digestive system and are excreted in the faeces. Analysis of this material allows information on the kingfishers diet to be obtained. Magnification: x 20 when printed at 10cm wide