In this paper, the problem of collaborative tracking of mobile nodes in wireless sensor networks is addressed. Aiming at an energy efficient solution, we propose a strategy of combining target tracking with node selection procedures in order to select informative sensors to minimize the energy consumption of the tracking task using the energy model by Heinzelman, 2000. We layout a cluster-based architecture to address the limitations in computational, battery power and communications of the sensor devices. The node selection problem is formulated as a cross-layer optimization problem that is solved using a greedy algorithm. To track mobile nodes two particle filters are used: the bootstrap particle filter and the unscented particle filter, ...