In this paper, we present a data collection protocol for wireless sensor networks employing a number of mobile sinks. For satisfying timely delivery of sensory data to mobile sinks, sinks are forced to visit only an appropriate number of rendezvous nodes while the remaining nodes send their data through multi-hop communication toward these nodes. The proposed approach achieves prolonged network lifetime by selecting energy rich paths for this multi-hop communication while the sink tours are not longer than a certain limit. Experimental results also validate the effectiveness of our approach compared with other competitive approaches from the literature.