Fig. 4. Choice of prey as a function of prey size (experiment III). Each data point represents the mean individual proportion of choices for the prey side (mean of means ± s.e.m.; 9 trials per bird per day; 2 test days; target distance to Y-junction 3.1 m). For a prey length of 5 cm, the results for three birds are for nine trials only. Broken line indicates critical value for significant choice of the prey side (0.75).