The deployment of a swarm of cooperative UAVs applications for the execution of distributed tasks has increased attention from both academia and industry researchers. The use of a group of UAVs instead of one single UAV offers many advantages like extending the mission coverage, providing a reliable ad-hoc networks services, and enhancing the service performance, to name a few. However, due to the highly dynamic nature of the swarm topology, the coordination of a large number of UAVs poses new challenges to traditional inter-UAV communication protocols. Therefore, there is a need for the design of new networking protocols that can efficiently support the fast-pace and real-time requirements of a coordinated swarm navigation in various environments. In this paper, we propose SEMRP a Swarm energy-efficient multicast routing protocol for UAVs flying in group formations. The main purpose of SEMRP is to facilitate the control and information delivery between UAVs while minimizing inter-UAV packet loss, packet re-transmission, and end-to-end delay. In this study we show how SEMRP achieves these objectives by taking into account various Quality-of-Service parameters like the network throughput, the UAVs mobility, and energy efficiency to ensure a timely and accurate information delivery to all members of a UAV swarm. The results of the conducted simulation using NS-2 advocate for the efficiency of our proposal through its to two presented versions (SEMRP-v1 and SEMRP-v2) in term of reducing the total emission energy (at least by 10 dBm), optimizing the End-to-End Delay by 44%, and increasing the packet delivery ratio by more than to 22% compared to SP-GMRF protocol.