Table 3.
Head position of mallard ducks in the four phases of landing flight as estimated from photos available in the internet
| Approach I | Approach II | Gearing | Touchdown | |
|---|---|---|---|---|
| Number of observations |
12 |
14 |
38 |
27 |
| Mean vector (μ) |
118° |
117° |
115° |
114° |
| Length of mean vector (r) |
0.991 |
0.993 |
0.994 |
0.995 |
| Circular standard deviation |
8° |
7° |
6° |
5° |
| Rayleigh test (p) | 2.54 × 10-11 | < 1012 | 7.9 × 10-7 | 1.67 × 10-6 |
The mean vector μ refers to the smallest angle between the line connecting the eye and the tip of the beak and the horizon (90°).