In this paper, we consider the sensor fusion problem for a team of robots, each equipped with monocular color cameras, cooperatively tracking multiple ambiguous targets. In addition to coping with sensor noise, the robots are unable to cover the entire environment with their sensors and may be out numbered by the targets. We show that by explicitly communicating negative information (i.e. where robots don’t see targets), tracking error can be reduced significantly in most instances. We compare our system to a baseline system and report results.