Most important characteristics of the Wireless Sensor Networks (WSNs) is selfconfiguration, in which each deployed sensor node configures itself with neighbor node and establishes the network topology. In the proposed work, an Unmanned Aerial Vehicle (UAV) based Reliable and Energy Efficient Data Collection Mechanism (REEDCM) is introduced using Wireless Sensor Networks with the Internet of Things (IoT). It mainly focuses on the effective data collection from the man un-attended area (i.e., red alerted area) including nuclear disaster zone, volcanic eruption, forest fire, and battlefield, etc. Battery energy is a major constraint of the WSNs, thus an efficient data collection mechanism is needed to enhance the energy efficiency and scalability. In REEDCM, a novel clustering mechanism is presented which selects the Cluster Head (CH) based on the residual energy, speed and number of neighbors. Besides, the UAV Data Collector (UAV DC) is used to gather the data directly from the CHs which in turn transmits the collected data to the Base Station (BS), then the BS shares the sensor information to the users through the Internet. From the simulation results, it is revealed that the proposed REEDCM provides better network performances in terms of average residual energy, average end-to-end delay, Packet Delivery Ratio (PDR) and throughput.