Table 1.
Flight altitudes and directions of migrating birds as recorded by tracking radar in the Beringia region from 30 July to 19 August 2005. (Altitudes are in metres above sea level with standard deviations (s.d.) in parentheses. Mean vector directions are given with mean vector lengths (r) within parentheses. Area C and D with bimodal directional distributions (figure 1) are also presented with datasets subdivided in east/west groups based on track directions. Mean altitudes and track directions are based on the total number of observations, while mean heading directions are based on the number of tracks given in parenthesis (cf. figure 1).)
| area | number of observations | altitude | direction | ||
|---|---|---|---|---|---|
| mean | maximum | track | heading | ||
| A | 49 (44) | 1267 (746) | 3569 | 88° (0.84) | 122° (0.81) |
| B | 32 (7) | 1468 (962) | 3442 | 99° (0.92) | 93° (0.97) |
| C | 67 (52) | 849 (640) | 2961 | 163° (0.27) | 116° (0.15) |
| C—west | 29 (27) | 570 (177) | 1075 | 268° (0.76) | 292° (0.60) |
| C—east | 38 (25) | 1062 (774) | 2961 | 121° (0.84) | 113° (0.97) |
| D | 252 (237) | 850 (594) | 3844 | 71° (0.44) | 147° (0.51) |
| D—west | 73 (71) | 705 (498) | 2245 | 290° (0.81) | 235° (0.86) |
| D—east | 179 (166) | 910 (621) | 3844 | 85° (0.91) | 120° (0.81) |
| E | 61 (52) | 2029 (965) | 4578 | 111° (0.62) | 127° (0.88) |
| F | 19 (7) | 1625 (235) | 3743 | 97° (0.69) | 89° (0.58) |
| G | 77 (75) | 1550 (919) | 4023 | 129° (0.81) | 171° (0.82) |
| all | 557 (474) | 1175 (855) | 4578 | 98° (0.51) | 143° (0.56) |