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Table 1 Distance ratios in relation to the shortest great circle distance for simulated trajectories based on different compass mechanisms in three examples of songbird migration systems (shown in Fig. 3)

From: Feasibility of sun and magnetic compass mechanisms in avian long-distance migration

  Breeding location Wintering location Distance of great circle route (km) Autumn + Spring Autumn Spring
Rhumbline route Fixed (menotactic) magnetic compass route Magnetoclinic compass route Time-comp. sunset compass route Fixed (menotactic) sunset compass route Time-comp. sunset compass route Fixed (menotactic) sunset compass route
Northern wheatear 70° N, 54° W 15° N, 15° W 6672 1.01 1.00 1.01 1.00 1.09 1.01 1.07
Willow warbler 68° N, 20° E 10° S, 30° E 8710 1.00 1.00 1.00 1.00 1.04 1.06 1.04
Pied flycatcher 68° N, 20° E 10° N, 10° W 6814 1.01 1.00 1.02 1.00 1.00 1.00 1.01
  1. The rhumbline route, the route associated with a fixed (menotactic) magnetic compass course and the magnetoclinic compass route do not differ between seasons, thus the distance ratios are given only once. For the other two compass mechanisms (time-compensated and fixed (menotactic) sunset compass) trajectories differ between autumn and spring seasons with different distance ratios as given in the table. Distance ratios (always > 1) are rounded to two decimals, meaning that ratios between 1.000 and 1.0049 are given as 1.00