Wireless sensor networks (WSN) are considered to be a promising concept for enabling numerous categories of applications for both civil and military applications. This can include dismounted soldiers teams, group of animals or a group of mobile robots, where agents are moving collectively and sharing the same goal (e.g., destination, source of food or location of enemy). In this paper, we investigate the impact of dynamic agents based on a flock mobility model on the efficiency of wireless communications. We consider N mobile sensor agents capable of sensing and sending data packets periodically towards a base station (leader agent) directly or via intermediate nodes (relay nodes). At each time period, a sensor node can verify if an event is sensed based on a probability approach and then generates a data packet that is to be sent towards the destination, or else a sensor node can act as a relay node to forward data packets from other nodes. We evaluate the performance of the sensor nodes network under varying levels of perturbation of the collective motion of agents. The performance metrics observed are the residual energy, the number of sensors nodes still alive, the average normalized velocity, the packet delivery ratio, the end-to-end delay, and the average number of hops. Simulation results confirm that the dynamic agents have a significant impact on both the sensor network lifetime and the reachability of communications.