Extended Data Fig. 5. Food preferences trials.

Birds were presented with a freely available mix of 40 mealworms, peanut granules and sunflower seeds for 1 hr on 2 days over 1 week at 6 sites (3 sites in T4 and T2). Trials were conducted 2 weeks after the end of the main experiment, in March 2014. Food choice was identified from video camera footage, and the trial was halted when all of one prey item was taken. Only great tits were included, but birds could not be individually identified. Birds clearly preferred the live mealworms to either peanut granules or sunflower seeds.