Figure 2

Departure directions of northern wheatears from Wales, Alaska. Departure directions were uniformly distributed towards 233° (Rayleigh test of uniformity: n = 15, R = 0.87, P < 0.0001; 95% CI: 218° – 249°, range: [205°, 288°]). The blue arrow shows the mean departure direction and its length being a measure of scatter is drawn relative to circle’s radius which is one (unit circle). Dashed lines give 95% confidence interval. Equal departure directions were plotted at slightly different directions so that they can be recognized (Table 1). The short arrows indicate the directions of the great circle route (336°, dark green), the constant magnetic course (262°, middle green) and the constant geographic course (251°, light green) from the study site towards Alaskan northern wheatears’ wintering area in sub-Saharan Eastern Africa.