The market of drones is expected to grow significantly by the near few years, while military, civil and commercial applications continue to emerge. In an earlier study we focused on the path planning problem for a swarm of UAVs for data gathering mission with the objective to minimize the travel duration with respect to the energy autonomy, a better fairness regarding tours and finally avoiding collisions among the drones of the same swarm. In this paper, we address the tracking and the data gathering issue and thus we evaluate both the received tracking and gathering packets rate under different conditions of speed and interference.