Fig. 3. Individual mean vector distributions relative to the orientation in the arena, in the No-Shift and Clock-Shift conditions. C, control (intact) pigeons; A, anosmic pigeons. All directions are calculated with respect to the home direction, which is set at 360°. Each inner line-and-circle represents the orientation mean vector with respect to home, calculated for a single pigeon. The outer circles indicate the mean vector directions. The inner white arrows represent the second order mean vectors. Confidence ellipses at 95%, 99% and 99.9%, according to the Hotelling one-sample test for vector distributions, are also reported.