In Noisy Miners, a social bird species, mobbing behaviour may arise in the presence of a predator. This behaviour is triggered by a 'chur' call given by an adult after identification of the predator. These calls present strong individual differences that are sufficient to permit individual differentiation. Scientists hypothesised that individual distinctiveness impacts mobbing responsiveness. To test this, they contrasted the response of noisy miners to playbacks of both familiar (calls recorded at the same location) and unfamiliar calls (calls recorded at a location greater than 800m distant) of the same species, and to white-noise control sequences synthesised to match the temporal structure of natural calls. The playbacks ranged from 10 to 30 seconds in duration, and were undertaken in the field at 10 different locations over the duration of 2 weeks. Each location was tested with the white noise condition, followed by the unfamiliar call and the familiar one, with an average of 200 minutes between trials. Below, asterisks indicate a significant difference between groups (*p <0.05, **p <0.01). Change in birds within 10 m of speaker following playback ** One Three Min after commencement of playback White noise Unfamiliar Familiar