Table 2. Wind assistance for six swifts Apus apus during spring migration calculated for four different pressure levels (925, 850, 700 and 500 hPa, respectively) representing altitudes 750 m, 1500 m, 3000 m and 5000 m, respectively.
Part 1, Congo-Liberia detour | Part 2, Crossing Sahara Desert | Part 3, Crossing Europe | ||||||||||
Swift | 925 | 850 | 700 | 500 | 925 | 850 | 700 | 500 | 925 | 850 | 700 | 500 |
7881 | 0.6 | 3.0 | 6.6 | 6.1 | 1.1 | 2.1 | 4.8 | 8.3 | −4.4 | −4.8 | −5.2 | −7.3 |
7882 | 0.5 | 1.8 | 7.2 | 6.3 | −1.0 | 0.9 | 5.8 | 9.3 | −0.3 | 0.9 | 3.6 | 5.3 |
7964* | −1.0 | −0.8 | −2.4 | −4.6 | −2.8 | −4.1 | −6.2 | −8.4 | ||||
7968 | −0.2 | 1.8 | 9.9 | 6.6 | −1.7 | 1.8 | 5.9 | 8.9 | −0.2 | 0.1 | −1.0 | −6.1 |
7969 | 1.5 | 3.5 | 6.6 | 7.4 | −0.5 | −1.3 | −2.7 | 3.4 | −0.9 | 0.0 | −0.3 | −2.8 |
7970 | 0.5 | 1.8 | 8.0 | 0.6 | −1.3 | 0.5 | 3.0 | 4.1 | 4.7 | 3.7 | 3.1 | 6.7 |
Mean | 0.6 | 2.4 | 7.7 | 5.4 | −0.7 | 0.6 | 2.4 | 4.9 | −0.6 | −0.7 | −1.0 | −2.1 |
Tailwinds are shown in normal font and headwinds are shown in bold font.
Did not make stopover in Liberia.