Conservation translocations are increasingly used to restore lost or declining populations; however, they have suffered from low rates of success. Translocation tactics that leverage species’ biology, such as social organisation, can be used to influence post-release performance. Animals released as part of reintroduction programmes are theorised to benefit from conspecifics from earlier releases, due to habitat cues and opportunities for social learning. While the benefits of between-cohort interactions are broadly assumed, empirical evidence is lacking. Using high-resolution GPS tracking across a population of bush stone-curlews, Burhinus grallarius, we investigated whether newly released animals (‘reinforcers’) interacted with previously released conspecifics (‘residents’), and whether these interactions impacted establishment. We found post-release outcomes for reinforcers varied depending on whether they shared social group membership with residents. Half the reinforcers formed social group co-membership with the residents and the other half did not. Reinforcers in the residents’ social group had greater release site fidelity, faster roosting area establishment, and better weight maintenance than did those that were not associated with residents. We found a reciprocal anchoring effect where the residents were also attracted to the reinforcers, which enhanced resident roost site fidelity. This has implications for the development of tactics that leverage social relationships to support translocation success.