Experimentally provided conspecific cues boost bird territory density but not breeding performance

Decision-making during different life-history stages requires information, which is obtained through own or others’ experience and interaction with the environment. In birds, song is important for territory defense and mate attraction. Although song has evolved to purposely convey information, it can be inadvertently exploited by conspecifics. Experiments attempting to attract focal species by playing back their song are numerous, yet the consequences for reproductive performance remain little understood. In 2013 and 2014, settlement, reproduction, and extrapair paternity of Phylloscopus sibilatrix were assessed in a randomized experiment. We hypothesized that territory number, reproductive performance, and extrapair paternity would be higher on song plots (wood warbler song playbacks during prebreeding periods) than on control plots (no wood warbler song playback). On song plots, 3 times more territories were established, settlement occurred faster, and maximum plot occupancy was highe...