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Table 2 Magnetic North versus geographic North as reference for the preferred heading direction (μ) during landing on water surface in the mallard (or diverse other species of water birds in the case of Botswana)

From: Directional compass preference for landing in water birds

Country

Magnetic declination

Number of flocks

Mean vector (mN) mμ

Mean vector (gN) gμ

Delta (mN, mμ)

Delta (gN, gμ)

Botswana I

-8°

264

356°/176°

344°/164°

12°

Botswana II

-15°

85

0°/180°

345°/165°

15°

Canada

17°

136

354°/174°

11°/191°

11°

Czech Rep.

1,095

7°/187°

10°/190°

10°

Estonia

168

14°/194°

21°/201°

14°

21°

Finland

218

9°/189°

17°/197°

17°

Italy

394

9°/189°

12°/192°

12°

Poland

381

13°/193°

17°/197°

13°

17°

  1. Mean magnetic declination (angular difference between geographic North and magnetic North) is given for each locality. gμ and mμ denote the axial mean vectors (given as XX°/XX°) with reference to magnetic North (mN) and geographic North (gN), respectively. All mean values are highly significant (Rayleigh test, p < 0.000000001, 0.462 < r < 0.848). Delta refers to the smallest angle between mN and mμ (and gN and gμ, respectively).