Cyathus stercoreus, commonly known as the dung-loving bird's nest, is a species of fungus in the genus Cyathus, family Nidulariaceae. Like other species in the Nidulariaceae, the fruiting bodies of C. stercoreus resemble tiny bird's nests filled with eggs. The fruiting bodies are referred to as splash cups, because they are designed to use the force of falling drops of water to dislodge and disperse their spores.