Fig. 6. Comparison between the mean vectors and their 95% confidence limits of pigeons with different experience and treatment. The diagrams of the upper row (N-S, No-Shift) and the lower row (C-S, Clock-Shift) refer to the orientation of pigeons released without or after clock-shift treatment, respectively. White sectors correspond to pigeons unfamiliar with the release site; grey and black sectors correspond to pigeons familiar with the release site, intact and anosmic, respectively.