— We propose a contention based reservation MAC protocol for a collaborative sensing scenario involving a set of surveillance UAVs communicating with a hub. Data transmission rights are secured via distributed contention access between the UAV nodes for K available mini-slots. Each node chooses a slot with probability p independently of the others and is only allowed one attempt in a frame. We investigate the optimal choice of p which maximizes the one-shot probability of success(or alternately, the expected number of successes), β, over the K minislots. We show that β is prone to local maxima and develop an empirical formula based on goodness-of-fit which matches the numerically obtained values closely.