39 Built-in hammer The oystercatcher feeds on seashore animals with hard shells such as mussels. Its long beak ends in a blunt tip that allows the bird to smash through shells. The sweep-net beak The avocet catches worms and other prey by striding forward and sweeping its upturned beak from side to side. Feeding on the shore Invertebrates that birds eat are plentiful on the shoreline, and range from crabs and shellfish to burrowing worms. Earthworms are eaten by garden birds, and also by some birds of prey. Snail shells Thrush skull The snail-smasher Thrushes eat a wide range of food – both plant and animal. Some feed on snails, which they smash open on stones. Blackcap skullAphids Caterpillar Probing warblers Warblers use their probing beaks to pick insects from leaves and bark. Invertebrate-eaters Many birds alter their diet throughout the year and eat whatever food is available. The number of insects and other invertebrates – animals without backbones – increases dramatically in spring, whereas in winter, food is scarcer and consists mainly of larvae (grubs) in wood or in the soil. Woodpecker skull Large insect-eaters The hoopoe uses its beak to pick large insects out of tree crevices, while the woodpecker chisels into the wood to find hidden grubs. Their long tongues have spear-like tips, which are used for impaling their prey. Beetle larvae Centipede Adult beetle Hoopoe skull Cockles Oystercatcher skull Mussel The crab’s hard skeleton is left uneaten by an oystercatcher. Worms Avocet feeding Ribbonworm Silt-burrowing lugworm Avocet skull