The female excavates a burrow, or colonizes an existing burrow that has been abandoned. Gould's monitor is a terrestrial or "ground-dwelling" reptile that excavates large burrows for shelter. Most excavates are unicellular, heterotrophic flagellates. The pair then excavates a burrow to start a new colony. The female dancing frog excavates in the streambed with her hindlimbs. "Nephrops" lives on patches of soft mud, in which it excavates burrow systems. The red-bellied woodpecker excavates holes in trees for nesting and roosting. The female excavates a hole, using her hind legs, and lays her eggs in it. The Acrasidae slime molds are the only excavates to exhibit limited multicellularity. The female selects the site for and excavates the redd. This bird excavates its own cavity nest, above ground (usually around ). He builds a fenced-in habitat near a cave which he excavates. It excavates a branching system of tunnels up to deep with several entrances. During the dry seasons, it excavates dung balls to reach the larvae inside. Because of aerodynamic drag, a Plinian eruption excavates a circular crater.