38 The majority of birds live on food that is incredibly abundant. This includes seeds, grass, nectar, insects, worms, and many other small animals. Finch skull Goose skull Seed-eaters Finches have short, sharp bills to break open seeds and nuts, though almost all of them feed invertebrates to their chicks. Leaves Pigeon skull Feeding on crops Pigeons and doves feed on seeds and leaves. Unlike all other birds, pigeons’ pointed bills enable them to drink without tilting their head back. Grain Living on grass Geese live on a diet of grass. Because it passes through their digestive system in just two hours, they need to feed almost constantly. Capercaillie skull Hooked beak for grasping leaves Conifer-eaters Species such as pheasants, grouse, and capercaillie from Northern Europe eat whatever plant food is available, although their preference is for seeds. In winter, the capercaillie feeds on the leaves of conifer trees. Seeds Needles of conifer trees Grass and waterplants eaten by geese Broad bill for tearing grass Eating plants and seeds As they have no teeth, birds have to crush plants and seeds before they digest them. They do this with their powerful beaks and a muscular organ called the gizzard, which grinds the food into pulp. Hard-cased seeds