Figure 1.

To determine whether grackles innovate stick tool use, three experiments were conducted. In Experiment 1.1, the stick was placed on the table in all three 5 min trials (a(i–iii)). In Experiments 1.2 (b(i–iii)) and 1.3 (c(i–iii)), the stick was inserted into the apparatus for three consecutive trials, each with a different position: position 1 (left; trials 1, 4, 7, 10, 13), 2 (middle; trials 2, 5, 8, 11, 14) and 3 (right; trials 3, 6, 9, 12, 15). Experiment 1.2 had three 5 min trials and Experiment 1.3 had three 5 min trials per day for 5 days totalling 15 trials where each trial began with a demonstration from the experimenter.