In this paper, we address the control problem of multiple Unmanned Aerial Vehicles (UAVs) flocking by using a behavior-based strategy. We conceive a behavior intending to adress the control design towards a successful achievement of the flocking task without fragmentation. Moreover, through its implemention in UAVs, no rendezvous point is needed to perform flocking. We design a control law, which is independent of the number of UAVs in the flock. We use the LQR control method to develop our strategy. Our proposed strategy deals with the flocking problem from a measurement-mapping perspective. Simulation results show two scenarios of aggregation and navigation of multiple UAVs.