Fig. 1. Initial orientation and homing performance of the free-flying (FF) and prisoner (P) pigeons. Each symbol represents one subject. (A) Initial orientation: the outer arrow represents the home direction; the inner arrow represents the mean vector distribution; N, number of birds; r, mean vector length; a, mean vector direction; hc, homeward component. (B) Homing performance: the homing time (in h); pigeons homed later than the day of the release and birds lost are indicated.