Table 1.
Statistics of bird flight in isolated pairs and in groups. NND denotes the first nearest neighbour distance, v3 denotes the velocity in the gravity direction, and aWing and aMove are the accelerations in the wing and movement directions, respectively. The values provided in the table are the means and standard deviations. Positive (negative) values of aMove mean speeding up (slowing down) and positive (negative) aWing implies turning right (left).
| event | total no. birds | trajectory length (s) | NND (m) | |v| (m s−1) | v3 (m s−1) | aWing (m s−2) | aMove (m s−2) |
|---|---|---|---|---|---|---|---|
| isolated pairs | 610 | 4.0±2.0 | 2.6±1.7 | 9.4±2.8 | −0.3±1.5 | −0.3±3.5 | −0.1±1.6 |
| flock 1 | 338 | 2.4±1.1 | 1.6±0.9 | 13.6±1.7 | −0.9±0.8 | −2.7±3.3 | −0.7±1.8 |
| flock 2 | 112 | 3.1±1.0 | 1.7±0.8 | 13.8±0.5 | −0.3±0.6 | −0.4±0.8 | 1.5±1.8 |
| flock 3 | 106 | 2.9±1.4 | 1.7±1.0 | 12.0±0.7 | −0.6±0.7 | −0.1±1.1 | 0.8±1.8 |
| flock 4 | 81 | 4.5±1.0 | 2.9±2.7 | 10.1±1.0 | −0.8±0.8 | −0.4±2.1 | −0.1±1.4 |
| flock 5 | 31 | 2.0±1.2 | 1.3±0.6 | 15.2±0.8 | −1.4±1.6 | −2.1±4.3 | −1.2±1.8 |
| flock 6 | 26 | 3.4±1.0 | 2.9±2.7 | 9.3±0.3 | 0.6±0.4 | −1.0±0.5 | −0.6±0.7 |