A pellet of kingfisher,カワセミのペリット

When you often may come across  this kind of sight when shooting wild birds, especially kingfishers and owls

A pellet, in ornithology, is the mass of undigested parts of a bird's food that some bird species occasionally regurgitate. The contents of a bird's pellet depend on its diet but can include the exoskeletons of insects, indigestible plant matter, bones, fur, feathers, bills, claws, and teeth. （Cited from Wikipedia）