English: Mole Fortress near Newburgh Mole fortresses are HUGE mounds, many times the size of a normal molehill. They have within them a network of tunnels and a nest chamber packed with dry grass. They often contain a store of earthworms weighing up to a kilogram. The mole bites off the heads of the worms which immobilizes them until they are eaten or until they grow another head in the spring of the next year. Mole fortresses are usually found in areas liable to flooding and act as a victualed refuge when the tunnel systems are waterlogged. Gardeners be afraid, be very, very afraid!