Food for night crawlers consists of many kinds of organic matter. They eat plant tissue (dead leaves and other plant debris), soil micro-organisms (protozoa, nematodes, bacteria, fungi, etc.), and the remains of larger dead animals. They feed by swallowing organic matter or bits of soil containing organic matter. This passes through their gut and is finally deposited as castings (poop) which the worms pass out when they are at the surface. Presumably this helps them to keep their tunnels clean and open.
