Urban dwellers know the plastic owl. In an effort to scare pigeons from roofs, ledges and window sills, they strap and screw them in place hoping that the appearance of a predator might yield the same results as the real thing. In the suburbs, plastic owls are conscripted to watch over backyard gardens warding off four-legged pests. But birds are smart. Once they learn that a predator look-alike poses no real danger, they resume their perches in bold and fearless defiance where they defecate on city buildings with impunity. Mammals too know that an owl that never moves is not an owl, so across America they eat vegetables in the shadows of fake predators.