For the first time, biologists noted American crows (Corvus brachyrhynchos) touching, attacking and attempting to mate with dead crows. Kaeli Swift, a doctoral candidate at the University of Washington, discovered this while showing one of her experiments to a film crew where she left a stuffed taxidermy crow on the ground. She was surprised to see a nearby crow attempting mating with the dead crow. Previous research showed crows sense danger when they see dead crows on the ground, but this new finding adds a twist, researchers say. They think the odd behavior may be caused by hormonal fluctuations that cause some crows confusion when responding to stimuli.