This article presents a display manipulation designed to support search tasks in which the location of the target is unknown and changes over time. The problem is analogous to that of a naval search task when there is an initial sighting and then the naval force must guide its search vehicles to reestablish contact with the fleeing target. The display manipulation visualizes a dynamic constraint on the area where a fleeing target can be found and adjusts its shape to the environment and to the search efforts. Forty participants without prior knowledge of search tactics completed 12 trials in an experiment that compared performance with and without the visualization aid and controlled for learning effects. The results suggest that this visualization improves performance in the dynamic search task. They further suggest that the visualization was easy to learn but that the learning effect did not transfer to a condition without visualization. The results have practical utility for both military and civil search tasks, and they are consistent with other research that emphasizes that control interfaces should make constraints in the task environment perceptually available.